Patent Publication Number: US-8990992-B2

Title: Mouthpiece for cleaning teeth with a mechanical drive train

Description:
This application claims the benefit or priority of and describes relationships between the following applications: wherein this application is a continuation of U.S. patent application Ser. No. 13/704077, filed Dec. 13, 2012, which is the National Stage of International Application No. PCT/IB2011/051792, filed Apr. 25, 2011, which claims the priority of U.S. Provisional Patent Application Ser. No. 61/357,260, filed Jun. 22, 2010, all of which are incorporated herein in whole by reference. 
    
    
     This invention relates generally to mouthpieces for cleaning teeth and more specifically concerns a mouthpiece with a mechanical drive train arrangement which includes a motor with an eccentric mass as part of the drive train. 
     The possibility of teeth cleaning by a mouthpiece appliance involves special structural considerations. Axial movement of mouthpiece sections, with bristles thereon, moving toward and away from sections of teeth is one possible arrangement. Typically, the mouthpiece is driven by a motor and two or more connecting arm assemblies which produce desired motion of two or more associated mouthpiece sections. With axial motion, the length of the movement stroke of the mouthpiece sections is limited because of space limitations in the mouths of users. The movement of the mouthpiece sections is also complicated since the bristles in the mouthpiece will in operation impact different teeth from different directions because of the particular physical arrangement of the teeth relative to the particular configuration of the mouthpiece. In addition, effective teeth cleaning by a mouthpiece assembly is complicated by the fact that the mouthpiece is not a handheld device per se like a toothbrush so that the user&#39;s hand cannot be a reference point which the forces produced in operation by the mouthpiece bristles can react against. 
     In one arrangement the mouthpiece is divided into three separate sections, two side sections and a center section, all three of which are driven in such a manner that a significant component of their movement is toward and away from the teeth to produce the axial, i.e. tapping, cleaning action. The drive train for producing such an action should be reliable and produce the desired action in an efficient and effective manner. 
     Accordingly, one aspect of the article is a mouthpiece appliance for cleaning teeth, comprising: an assembly for receiving teeth which includes two opposing side portions and an intermediate center portion, wherein the side portions and the center portion include bristle sections which are adapted to clean teeth of the user when contact is made between the bristle sections and the surfaces of the teeth; a motor assembly with an output shaft and an eccentric mass or crankshaft mounted thereon; first and second opposing drive arms extending outwardly from and connected to the motor assembly so that the distal ends of the drive arms move outwardly and inwardly together; connecting arms connected to the drive arms and at one end to the side portions of the teeth receiving assembly so that as the motor shaft rotates, the side portions of the teeth receiving assembly move in and out, toward and away from the teeth, producing cleansing of the teeth; and a center member driven by the motor assembly, directly or by action of the two connecting arms, to move the center portion of the teeth receiving assembly toward and away from the teeth, producing cleansing of the teeth. 
     Another aspect of the article is a mouthpiece for cleaning teeth, comprising: an assembly for receiving teeth which includes two side portions and an intermediate center portion, wherein the side portions and the center portion include bristle sections which are adapted to clean teeth upon contact between the bristle sections and the teeth of the user; three motor assemblies, each with an eccentric weight mounted on an output shaft thereof; first, second and third drive arms which extend, respectively, between the respective motor assemblies and the side and center portions of the teeth receiving assembly; and first, second and third spring assemblies which connect the drive arms to a body portion of the appliance, wherein each of the spring assemblies, respectively, is configured to permit movement of their associated drive arm in one direction which results in cleansing of the teeth, but substantially prevents movement of the same drive arm in other directions. 
     A still further aspect of the article is a mouthpiece appliance for cleaning teeth, comprising: an assembly for receiving teeth which includes two opposing side portions and an intermediate center portion, wherein the side portions and the center portion include bristle sections which are adapted to clean the teeth of the user when contact is made between the bristle sections and surfaces of the teeth; a motor assembly, including an eccentric mass mounted on a drive shaft of the motor; an inner frame member which is connected to the motor assembly, the motor assembly and the inner frame member being supported so as to move toward and away from the teeth, but not in other dimensions; an outer frame member which includes an upper portion and a lower portion connected by separate hinge members, wherein the lower portion is fixed within the appliance and wherein the upper portion terminates in two free ends defining a distance therebetween; two connecting arms which extend between the inner frame and the upper portion of the outer frame, wherein rotation of the motor and the eccentric will produce an out and in movement of the upper portion of the outer frame member about the hinge members; two opposing side portion drive arms which extend respectively from the free ends of the upper portion of the outer frame member to the side sections of the teeth receiving assembly; and a center portion drive assembly extending between the inner frame member and the center portion of the teeth receiving assembly, such that of rotation of the motor and the eccentric results in an in and out movement of the side and center portions toward and away from the teeth, producing cleansing of the teeth by contact between the bristles and the teeth. 
     Another aspect of the article comprises: A mouthpiece appliance for cleaning teeth, comprising: an assembly for receiving teeth which includes two opposing side portions and an intermediate center portion, wherein the side portions and the center portion include bristle sections which are adapted to clean teeth of the user in operation; two connecting arms which cross one another and which are connected at one end to the opposing side portions of the teeth receiving assembly and are pivotally connected where they cross; a first linear motor connected between the other ends of the two connecting drive arms, wherein in operation the first linear motor drives the one ends of the drive arms toward and away from each other, resulting in the side portions moving toward and away from the teeth, producing cleansing of the teeth; a movable central member attached to the center section of the teeth receiving assembly and a fixed member positioned between the two drive arms a distance away from the central member; and a second linear motor extending between the fixed and movable members, wherein in operation the movable central member and the center section of the teeth receiving assembly move toward and away from the teeth, producing cleansing of the teeth. 
    
    
     
         FIG. 1  is a top view of a first embodiment of a mouthpiece assembly. 
         FIG. 2  is an isometric view of the mouthpiece assembly of  FIG. 1 . 
         FIG. 3  is a simplified diagram of the drive train arrangement for the mouthpiece assembly of  FIGS. 1 and 2 . 
         FIG. 4  is a simplified diagram of an alternative drive train arrangement. 
         FIG. 5  is a simplified diagram of another drive train arrangement. 
         FIGS. 6-8  are partial top and perspective views of another embodiment. 
         FIG. 9-13  are perspective, cross-sectional and top views of another embodiment. 
         FIG. 14  is a top view of a variation of the embodiment of  FIGS. 9-13 . 
         FIG. 15  is a top view of a variation of the embodiment of  FIGS. 1-3 . 
         FIGS. 16 and 17  are top views of variations of the embodiment of  FIG. 9-13 . 
     
    
    
       FIGS. 1 and 2  show a first embodiment for a teeth cleaning mouthpiece with a mechanical drive train. The mouthpiece assembly  10  includes a teeth receiving assembly  12  which includes two generally opposing side portions  14 ,  16  and an intermediate center portion  18  positioned between the two side portions. The teeth receiving assembly  12  typically comprises a base of plastic material configured to receive the teeth of the user. The teeth receiving assembly could be adapted to include just the bottom teeth, or just the top teeth or both the top and bottom teeth. The individual side and center portions are formed so as to extend along the upper surfaces and the side surfaces of the teeth, covering the teeth surfaces. 
     Positioned on the interior surfaces of the side and center portions of the teeth receiving assembly are conventional bristles  20  which are adapted to produce a teeth cleaning action in operation of the mouthpiece. The bristles are similar to those used in conventional toothbrushes. However other elements could be used for teeth cleaning as well. It should be understood that the three portions of the teeth receiving assembly can take various arrangements and configurations. Typically, the teeth receiving assembly of the present invention will include three separate portions, although fewer than three portions could be used, such as just two portions, each covering up to one-half of the teeth surfaces, or in some cases just a center portion, covering a portion of the total number of teeth. More than three sections could also be used, with each section being driven independently or jointly with other sections, depending on the particular arrangement. 
     The three portions  14 ,  16  and  18  of the teeth receiving assembly  12  are driven mechanically. The center portion  18  is driven directly toward and away from the front teeth of the user. The two side portions are driven somewhat at an angle relative to the teeth in the side regions, i.e. those teeth to the rear of the front teeth, due to the particular mechanical arrangement of the drive train assembly, as discussed in detail below. There is, however, a significant component of the motion directed toward and away from the teeth. 
     A drive train assembly referred to generally at  24  includes a DC drive motor  26  and an eccentric mass  28  which is mounted on the output shaft of the motor. Alternatively, an eccentric crankshaft can be used. In the embodiment shown, the DC motor runs at a frequency of 10-100 Hz, preferably 25 Hz. The distance of the offset weight is 0.05-3 mm, preferably 0.1 to 0.5 mm. The characteristics of the motor and the eccentric, however, can be varied. The drive train assembly further includes two opposing drive arms  32  and  34  which extend directly outwardly from the motor  26  and are connected to the motor in such a manner that the distal ends  36  and  38  of the drive arms  32  and  34 , respectively, move inwardly and outwardly together as the drive motor shaft and the eccentric rotate. 
     The length of the stroke or the distance that that the distal ends  36  and  38  move is approximately 0-1-2 mm, preferably 0.1 mm. Rotatably connected to distal ends  36  and  38  of the drive arms are opposing connecting arms  40  and  42  which extend toward the teeth receiving assembly and connect at free ends  41  and  43  thereof to side portions  14  and  16  of the teeth receiving assembly. In the embodiment of  FIGS. 1 and 2 , and further illustrated more functionally in  FIG. 3 , the connecting arms  40 ,  42  extend to the rear, away from the teeth, past distal ends  36  and  38  of drive arms  32 ,  34  to connecting points  46  and  48 , about which the connecting arms rotate as the motor shaft and eccentric rotate. Extending from connecting points  46  and  48  and angled toward each other are two lower adjusting arms  52  and  54 , connected at a center pivot point  56 . Extending from pivot point  56  away from motor  26  is an adjusting arm  58  at the end of which is an adjustment knob  60 . Rotation of adjustment knob  60  will move adjusting arm  58  toward or away from the motor, expanding or contracting the distance between the free ends  41 ,  43  of connecting arms  40  and  42 , to accommodate wider positioned teeth in users&#39; mouths. Although the adjustable feature of arms  52  and  54  with adjusting arm  58  is convenient, it is not necessary to the present invention. 
     In operation, the connecting arms  40 ,  42  will pivot about connecting points  46  and  48 , as the two drive arms  32 ,  34  move in opposing directions, inwardly and outwardly by the action of motor  26 . This results in a movement of the free ends  41 ,  43  of the connecting arms of 0.1-5 mm, preferably 0.5 mm, towards (against) and away from the respective side regions of the teeth. In the embodiment shown the connecting arms  40 ,  42  first angle slightly inwardly from their connection points with distal ends  36  and  38  of drive arms  32 ,  34 . At this point, approximately 7.5 mm from the distal ends  36  and  38 , the two connecting arms  40 ,  42  first angle outwardly at an angle which is approximately 5-15°, up to an approximately 40° inclusive angle, in the embodiment shown. This angle, however, can also vary. 
     The above arrangement of  FIG. 1-3  produces a reliable in and out action of the side portions, with resulting effective cleansing of the side regions teeth as the bristles make contact with the teeth. 
     In the embodiment of  FIGS. 1-3 , the center portion  18  of the mouthpiece receiving assembly is driven directly by a center connecting arm  64 . Connecting arm  64  rides in bearings  65  to produce a smooth movement. In the embodiment shown, the length of the stroke of center portion is approximately 0.5 mm, but can vary, such as within a range of 0.25 mm-1.0 mm or even more, in some cases, even to 10 mm. 
     An alternative to the arrangement of  FIGS. 1-3  is shown diagrammatically in  FIG. 4 . In this arrangement, a motor and eccentric assembly  61  drives two opposing side drive arms  70  and  72  outwardly and inwardly, as with the embodiment of  FIGS. 1-3 . This action drives opposing connecting arms  76  and  78  outwardly and inwardly about a single fixed rear pivot point  80 . The free ends  77 ,  79  of connecting arms  76  and  78  are connected to side sections of the teeth receiving assembly (not shown), so that the side sections move against and away from the teeth, providing a cleaning action. 
     Connecting arms  76  and  78  are connected by a center arm  82  at spaced pivot points  83 ,  85 . Center drive arm  82  itself has a pivoting center point  86 . Connected to center drive arm  82  is an intermediate arm  90  which is connected to a center section  91  of the teeth receiving assembly. The intermediate arm  90  moves toward and away from the teeth through a bearing  92 . Both of the embodiments of  FIGS. 1 ,  2  and  3  and  FIG. 4 , respectively, produce the desired in and out movement of three separate teeth receiving sections, making bristle contact with the teeth to produce cleaning of the teeth. The embodiment of  FIG. 4  produces movement of the center section by virtue of movement of the side section connecting arms instead of directly from the motor and eccentric assembly. 
       FIG. 5  shows another embodiment in simplified schematic form. It includes two elongated connecting arms  98  and  100  linked by a center pivot point  102 . Linear motor  104  extends between lower ends  106 ,  108  of the connecting arms  98  and  100 . In operation, linear motor  104  will move ends  106  and  108  directly toward and away from each other, which will result in opposing ends  110  and  112  of arms  98 ,  100  which are connected to the side portions  111 ,  113  of a teeth receiving assembly  114  and moving toward and away from the teeth, with the bristles on the side portions making contact with the teeth to produce a cleansing action for the side regions of the teeth. A second linear motor  118  is positioned between a fixed member  120  and a moveable member  122  which is attached to a center section  124  of the teeth receiving assembly. The motor  118 , and members  120  and  122  are positioned between pivot point  102  and the teeth. The linear motor  118  will move the center section  124  towards and away from the teeth producing a cleansing action on the center portion of the teeth when the bristles on the center section make physical contact with the teeth. 
     Another embodiment is shown in  FIGS. 6-8 . This embodiment also includes a DC motor assembly  150 , which includes a motor and an eccentric mass like that for the above embodiments. The motor assembly  150  is connected to an inner frame member  148  by opposing connecting hinge members  151 ,  151 A and by a connecting arm and hinge member  152 . The inner frame member  148  is shaped in such a way, with hinge members  151 ,  151 A that horizontal (side-to-side) movement of the inner frame is limited, yet movement in the vertical direction is free, toward and away from the teeth receiving assembly. The inner frame member  148  is supported by a bearing  153  which is fixed to the appliance so that the inner frame member with the connecting hinge members are free to move relative to the motor. The inner frame member  148  is secured to an outer frame member  158  by two elongated connecting arms  160  and  162  ( FIG. 8 ). The connecting arms  160  and  162  are connected to the inner and outer frame members by hinge elements  164  located at the opposing ends thereof. In the embodiment shown, the connecting arms  160 ,  162  extend at an angle of approximately 45° from the horizontal between the inner and outer frame members. Both the inner and outer frame members in the embodiment shown are made from steel, although they could be made from other materials, such as plastic, as well. Typically, the hinge members, however, will be made from steel. 
     The outer frame member comprises upper and lower portions  166  and  168  with hinge elements  170  connecting the two portions. Lower section  168  is fixed to the frame  169  of the appliance so that it does not move in operation, while the upper portion  166  is free to move outwardly about hinge members  170  in response to movement of the inner frame member toward and away from the teeth by action of the motor assembly, specifically rotation of the motor drive shaft and the eccentric mass mounted thereon. Connecting arms  160 ,  162  extend to the upper portion of the outer frame member, and thereby provide the required motion of the upper portion of the outer frame member. 
     Extending from the upper end of inner frame member  148  is a center drive assembly  172 , which includes a center frame arm  173  ( FIG. 8 ), the distal end of which drive assembly  172  is connected to a center portion  177  of the teeth receiving assembly  174 . The upper portion  166  of the outer frame member  158  terminates in two spaced-apart free ends  176  and  178 . Pivotally connected to the free ends  176 ,  178  are side portion drive arms  179  and  180  which drive the opposing side portions of the mouthpiece side portions  182  and  184  of the teeth receiving assembly. In operation, rotation of the DC motor shaft will result in up/down movement of the inner frame member toward and away from the teeth receiving assembly, which results in a movement of the center drive assembly  172  directly toward and away from the teeth and an outward/inward movement of drive arms  179  and  180  about hinge members  170 , resulting in movement of side portions  182  and  184  of the teeth receiving assembly toward and away from the teeth, cleaning the teeth by contact between the bristles on the teeth receiving assembly and the teeth. 
     In the embodiment of  FIGS. 6-8 , side portion drive arms  179  and  180  extend downwardly with extended portions  188  and  190  from their point of pivoting connection with free ends  176  and  178  of the upper portion of the outer frame member. The extended portions  188  and  190  of arms  179  and  180  extend downwardly and then outwardly (angling upwardly in sections  193 ,  195 ) to overlap a part of the upper portion of the outer frame member. Each extended portion  188  and  190  includes a slot  192  near the free ends thereof, in the angled sections  193 ,  195 . Riding in each slot  192  is a pin  194  ( FIG. 7 ) which extends from the upper portion of the outer frame member. This arrangement, while not necessary, allows the two side portion drive arms to be positionable so as to accommodate different sized teeth arrangements, similar to the adjustment member in the embodiment of  FIGS. 1-3 . 
       FIGS. 9-13  show another embodiment for a teeth cleaning mouthpiece with a mechanical drive train.  FIG. 9  shows a mouthpiece with a teeth receiving assembly  196  which has two opposing side portions  197 ,  198  and an intermediate center portion  199 , like the embodiments shown above. Fewer or more individual portions could be used, however. The two side portions and the center portion are driven separately by DC motors  200 - 201  for the side portions and  202  for the center portion. Each DC motor has an eccentric mass mounted on an output shaft thereof. The desired frequency range of the motor is 20-270 Hz, preferably approximately 100 Hz. In the embodiment shown, the offset radius of the eccentric will be between 0.2 and 10 mm, preferably approximately 2 mm, while the mass of the eccentric will be between 0.03 and 20 grams, preferably approximately 5 grams. 
     Extending from the motor assemblies are three drive arms, with drive arms  205  and  206  being associated with the side portions of the teeth receiving assembly and drive arm  208  being associated with center portion  199 . 
     The embodiment of  FIGS. 9-13  includes supporting spring assemblies  212 - 214  which extend downwardly from each drive arm to a frame/housing portion of the mouthpiece appliance. The springs  212 - 214  are all made from spring steel but have different configurations to provide the required motion for each separate portion of the teeth receiving assembly of the mouthpiece. The springs could also be made from other materials, such as plastic. 
     The springs for the two side portions have an X shape in cross-section, shown in detail in  FIG. 12 .  FIG. 12  also shows motor  200  and its eccentric mass  200 A. In the embodiment shown, the springs  212  and  214  are approximately 20 mm long, 5 mm wide and 0.2 mm thick. The X configuration is designed so as to be weak in the rotational dimension, thereby permitting movement in the rotational direction which in turn permits the ends of the drive arms  205 ,  206  and the side sections to which they are connected to move in and out, toward and away from the teeth, resulting in cleansing of the side teeth with bristle contact with the teeth. The spring assembly for center drive arm  208 , shown in  FIGS. 11 and 13 , includes two spaced metal leaf springs  220 ,  222 .  FIGS. 11 and 13  also show motor  201  and its eccentric mass  201 A. The two leaf springs are separated by approximately 15 mm, and are approximately 20 mm long, and 5 mm wide and 0.2 mm thick. The leaf springs are oriented laterally across the drive arm  208 , so as to permit motion of the drive arm toward and away from the teeth, due to the relative thinness of the leaf springs, but prevents motion laterally, due to the width of the spring and rotationally, due to the use of two springs and the spacing between them. 
     The configuration of the springs is important, since it allows movement of the drive arm in a desired direction while tending to prevent movement in other directions. 
     The advantage of the drive train shown in  FIGS. 9-13  is that it is force driven, meaning that the maximum force produced against the teeth cannot exceed a certain value, determined by the mass of the eccentric, the eccentric offset and the RPM of the motor. As is clear from the above, the drive train of  FIGS. 9-13  is actually three independent drive trains, so that the separate sections of the mouthpiece can be moved completely independently. 
     While the spring arrangement shown in  FIGS. 9-13  produces an in and out movement of the teeth receiving sections, generally toward and away from the teeth, other spring arrangements can be produce different brushing actions. One such arrangement is shown in  FIG. 14 . This arrangement produces an action of each individual section  210 - 212  along or across the surfaces of the teeth. In this arrangement, two leaf springs are provided for the center section. The leaf springs  214 ,  215 , however, are oriented at 90° to that of the embodiment of  FIGS. 9-13 , i.e., the two leaf springs are positioned parallel with the drive arm for the center sections. The leaf springs have the same length and the same thickness, and are separated by the width of the connecting arms, i.e. 10 mm. The action of the associated DC motor and the eccentric produces a sweeping motion of the center section of the teeth receiving assembly, back and forth across the surfaces of the teeth, as opposed to in and out, towards and away from the teeth, because the arrangement of the springs  214 ,  215  tends to prevent in and out motion of the connecting arm and the center portion of the teeth receiving assembly. 
     The leaf spring assemblies for driving the side sections each comprise two spaced leaf springs  216 ,  217 . These leaf springs will be oriented laterally relative to the length of the connecting arms. In the embodiment shown, they will be spaced by approximately 2.5 mm. With respect to these two assemblies, as the DC motor with the eccentric mass turns, the drive arms and the side sections will move back and forth parallel with the surfaces of the teeth. The action of the embodiment of  FIG. 14  produces a scrubbing cleaning action with the bristles, instead of a tapping cleaning action, as for  FIG. 9-13 . 
     Other motions of the teeth receiving sections can be accomplished using different spring arrangements. 
     FIGS.  15  and  16 - 17  illustrate mouthpiece appliances with teeth receiving assemblies comprising just two sections. In  FIG. 15 , a teeth receiving assembly comprises two sections  220  and  222 . A DC motor/eccentric mass assembly  223  drives two opposing drive arms  224  and  226 , which in turn drive two connecting arms  228 ,  230 . The connecting arms are connected to sections  220  and  222 . This arrangement produces back and forth movement of the drive arms, toward and away from the teeth. 
       FIG. 16  is comparable to the embodiment of  FIGS. 9-13 , with two cleaning sections  232 ,  234  comprising the teeth receiving assembly. An arrangement of leaf springs permit in and out action of the associated drive arms. For each drive arm  236 ,  238 , there are two spaced leaf spring, e.g. leaf springs  240  and  242  for drive arm  236 . For  FIG. 17 , with two sections  250 ,  252  and two drive arms  254 ,  256 , two X configuration spring assemblies  258  and  260  provide a rotating action of the drive arms, about the motor assemblies, with corresponding movement of the two cleaning sections. 
     While the embodiments described above include a DC motor, an AC motor can also be used. Further, while bristles have been disclosed for cleaning, other cleaning elements, such as foam elements, could be used effectively as well. 
     Accordingly, a mouthpiece appliance to clean teeth has been disclosed which includes a teeth receiving mouthpiece, comprising three sections or in some cases two sections, for cleaning of the teeth. More than two sections is also possible A mechanical drive train using a DC motor and an eccentric mass is used to drive separate connecting arms which are connected to the mouthpiece sections. In one embodiment a single motor assembly is used with an arrangement of connecting arms to produce desired in and out motion of the brushhead sections toward and away from the teeth. In another arrangement, a separate motor is used for each mouthpiece section, with a spring support arrangement for each drive arm to provide the cleansing action for the teeth, including both in and out action or action across the teeth. With this embodiment, other cleansing motions can be achieved. 
     Although a preferred embodiment of the invention has been disclosed for purposes of illustration, it should be understood that various changes, modifications and substitutions may be incorporated in the embodiment without departing from the spirit of the invention, which is defined by the claims which follow.