Patent Publication Number: US-2005139227-A1

Title: Dental flossers

Description:
BACKGROUND OF THE INVENTION  
      This invention relates to dental flossers and more particularly to electrically powered dental flossers which reciprocate a length of floss for cleaning in-between teeth and over gums.  
      Dental flossers are known which include a bow for supporting a short length of floss and an electrically powered version of this is shown in U.S. Pat. No. 5,762,078 in which a flosser head for a toothbrush driver incorporates a mechanism for reciprocating the flosser bow linearly with respect to the major axis of the toothbrush driver. However, it has been found that a preferred configuration is for the floss to be stretched over a pair of prongs for reciprocation laterally with respect to the major axis of the toothbrush driver and a number of arrangements have been proposed, such as that shown in U.S. Pat. No. 5,085,236 where a dental flossing attachment adapted to be mounted on a drive shaft of an electric toothbrush driver incorporates a floss supply spool and a floss take-up spool at the base of the prongs in the attachment. This obviates the need for threading of the floss every time new floss is required, through the use of a floss advancing mechanism, the entire arrangement being disposable so that when fresh dental floss is exhausted the dental flossing attachment is removed and discarded, with a new attachment then being snapped into place on the toothbrush driver as desired.  
     SUMMARY OF THE INVENTION  
      The present invention provides in a first aspect a dental flosser attachment for a toothbrush driver in which dental floss from a spool on or in the attachment is fed via a floss quick release locking mechanism to a floss receiving end of one of a pair of prongs extending from the body of the attachment to a floss receiving end of the other prong and back to the quick release mechanism such that the free end of the floss may be pulled to tension the floss between the prongs, whereafter the quick release mechanism is releasably locked to retain the tension of the floss therebetween, including across the prongs, the quick release mechanism being mounted for reciprocable rotation relative to the prongs to thereby cause the floss to oscillate therebetween when the flosser attachment is activated by the toothbrush driver.  
      Preferably, the dental flosser attachment is driven by a motor via a drive train in which circular motion is translated into oscillating or reciprocating movement, such as by the use of a bell-crank mechanism or a crown gear and associated spur gear, to which crown gear is eccentrically mounted a drive pin attached to one end of a drive link, the other end of which is attached to the quick release mechanism and/or a platform on which a quick release mechanism is mounted.  
      Conveniently, the quick release mechanism may itself comprise a pair of fixed clamp jaws, against each of which a pair of slideable clamp jaws are engageable to trap respective parts of a length of floss therebetween, the intermediate length of floss being at least partially supported by the prongs of the flosser attachment to enable flossing by a user of the combination flosser attachment and toothbrush driver. Preferably, the slideably mounted clamp jaws have cam surfaces co-operable with projections on or in a rotatable knob adjacent thereto such that upon partial rotation of the knob in one direction the slideable jaws are forced apart so as to engage with the fixed clamp jaws or floss therebetween. Conveniently, the slideable clamp jaws are biassed to their open position by means of a spring arm which may conveniently be made of nylon. The spring arm may comprise two springs, one for each slideable clamp jaw, and may further be integrally formed with a centrally disposed collar relative to the rotational axis of the knob.  
      In an alternative embodiment, the slideably mounted clamp jaws may be forced to their closure position against the fixed clamp jaws by means of an over-centre cam locking arrangement including a rotatable drive plate having diagonally opposite cam surfaces which engage innermost surfaces of the slideable clamp jaws such that upon rotation of the drive shaft in one direction the jaws are forced apart to engage with the fixed clamp jaws or floss therebetween. Conveniently, drive links are attached to the drive plate to provide an over-centre cam locking arrangement whereby the slideable clamp jaws are retained in their locked position when the drive plate is rotated slightly beyond the point by which the slideable clamp jaws are in their initially locked positions, such that upon rotation of the drive plate in the opposite direction the slideable jaws become unlocked and can be returned to their original open position.  
      In a further alternative embodiment, the quick release mechanism may be in the form of a slotted disc in which a pair of symmetrically disposed spiral slots act as cam surfaces co-operable with projections, such as drive pins, attached to the slideable clamp jaws, either directly or indirectly, such that upon rotation of the slotted disc the slideable jaws are forced to move from an open to a closed position relative to the fixed jaws and vice versa.  
      In accordance with a second aspect of the invention there is provided an electrically powered flosser comprising a body portion, a head portion from which extend a pair of prongs for receiving floss therebetween, the head portion including a quick release mechanism for releasably locking a length of floss between the prongs of the flosser, the quick release mechanism being mounted for reciprocable movement such that floss between the prongs oscillates on movement of the quick release mechanism when locked, the quick release mechanism being drivingly connected to a motor in the body portion. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention will now be described, by way of example only, with reference to the accompanying drawings in which:  
       FIG. 1  is a front perspective view of a dental flosser attachment for a toothbrush driver showing the quick release mechanism in its open, unlocked, position,  
       FIG. 2  is a view corresponding to that of  FIG. 1  showing the quick release mechanism in its closed, locked, position,  
       FIG. 3  is a perspective view of the attachment of  FIG. 1  from the front and other side showing part of the locking button assembly removed,  
       FIG. 4  is a top view to that shown in  FIG. 3 , showing part of the quick release mechanism exposed,  
       FIG. 5  is an underneath view of part of the locking mechanism,  
       FIG. 6  is a perspective view showing the drive train from an electric motor (not shown) to the quick release mechanism,  
       FIG. 7  is a top plan view of the arrangement of  FIG. 6  with part of the locking mechanism removed,  
       FIG. 8   a  is a plan view of an alternative quick release mechanism shown in its unlocked position,  
       FIG. 8   b  is a schematic plan view of the quick release mechanism of  
       FIG. 8   a  in its over-centre locked position,  
       FIG. 9   a  is an exploded sectional elevation of the quick release mechanism of  FIG. 8   a  along the line x-x,  
       FIG. 9   b  is a sectional elevation along the line y-y of part of the quick release mechanism of  FIG. 9   a,    
       FIG. 10  is a plan view of a further alternative quick release mechanism using a cam locking mechanism,  
       FIG. 11  is a perspective view of a still further alternative quick release mechanism using an alternative cam locking mechanism to that shown in  FIG. 10 ,  
       FIG. 12  is a view corresponding to part of the arrangement shown in  
       FIG. 11  but with the rotatable actuation knob shown removed, and  
       FIG. 13  is an underneath plan view of the rotatable knob shown in  FIG. 11 . 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS  
      Referring firstly to FIGS.  1  to  5 , a flosser head attachment shown generally at  1  includes a body portion  2  for fitting to the end of an electrically operated toothbrush driver (not shown) in place of a toothbrush attachment, the body portion  2  containing a spool of dental floss (not shown), from which spool of floss extends a continuous line of floss  3 , initially through a quick release mechanism shown generally at  4  to a floss receiving end  5  of one of a pair of prongs  6  and then via a floss receiving end  7  of the other prong back to the quick release mechanism  4 , around a peg  8  extending from the body portion  2  and thereafter into a notch  9  in the body portion  2 , which notch includes at the base thereof a blade (not shown) for cutting used lengths of floss  3  as required.  
      The quick release mechanism  4  comprises an elliptical pivotally mounted clamp platform  10  having fixed clamp jaws  11 ,  12  at respective ends thereof, against which oppositely disposed slideably mounted clamp jaws  13 ,  14  (best seen with reference to FIGS.  3  to  5 ) can bear to releasably capture or lock the line of floss  3  when a rotatable button or knob  15  is rotated to the position shown in  FIG. 2 , in which position the length of floss  3   a  trapped between the clamp jaws  11 ,  13  and  12 ,  14  prevent further linear movement of the floss  3   a  relative to the quick release mechanism  4 .  
      The outer sides of the prongs  6  are channel shaped such that when the prongs  6  are placed into the mouth of a user of the device respectively opposite portions of the length of floss  3   a  do not rub against the inside of the mouth of the user in these regions.  
      FIGS.  3  to  5  collectively show how the quick release mechanism for the floss  3  works. In  FIGS. 3 and 4  the knob  15  has been removed to reveal the slideably mounted clamp jaws  13 ,  14  disposed between the fixed clamp jaws  11 ,  12  on the moveably mounted platform  10 . The slideably mounted clamp jaws  13 ,  14  are received between respective side walls  16 ,  17  of the platform  10  and each is connected to the other via a pair of resiliently deformable arcuate spring arms  18 ,  19  integral with and extending outwardly from a central collar  20  keyed to a centrally disposed drive shaft  21  to which the platform  10  is also drivingly secured in a manner to be explained with reference to  FIGS. 6 and 7 . Each of the slideable clamp jaws  13 ,  14  have respective cam surfaces  22 ,  23  by which a pair of diagonally opposite pins  24 ,  25  (shown in  FIG. 5 ) on the underside of and protruding from the knob  15  can force the slideable clamp jaws  13 ,  14  outwardly towards the fixed clamp jaws  11 ,  12  when the knob  15  is rotated to the position shown in  FIG. 2 , whereafter the pins  24 ,  25  then rest in respective detents  26 ,  27  to releasably lock the floss  3  against linear movement until the knob  15  is returned to the position shown in  FIG. 1 . A stop member  28  is provided on slideable clamp member  13  to prevent the knob  15  from being rotated too far.  
       FIG. 5  is an underside view of the knob  15 , slideable clamp jaws  13 ,  14  and associated spring arms  18 ,  19  and collar  20 , from which it will be apparent that upon rotation of the knob  15  and hence pins  24 ,  25  in the anticlockwise direction arrowed, the pins rise up the cam surfaces  22 ,  23  on the slideably mounted clamp jaws  13 ,  14  to force them apart in opposite directions, as arrowed, the spring arms  18 ,  19  providing for their return to the position shown when the knob  15  is returned also to the position shown.  
      In  FIGS. 6 and 7  there are shown respective views of the drive train from a motor (not shown) to the moveably mounted platform  10 , shown in  FIG. 6  with the knob  15  in place and in  FIG. 7  without it in place. A drive shaft assembly shown generally at  29  is secured to the inside of the body portion  2  (not shown) by a bushing  30  and ends with a spur gear  31  secured to the end thereof for rotation therewith. The spur gear  31  meshes with a crown gear  32  mounted on a spindle  33  so that rotation about the major axis of the drive shaft assembly  29  is converted into rotation about the major axis of the spindle  33 .  
      Extending from the upper end of the crown gear  32  is an eccentrically projecting drive pin  34  (seen more clearly with reference to  FIG. 7 ) to which is attached a drive link  35 , the other end of which is secured to a secondary drive pin  36  extending from an edge region of a drive plate  37  fixed for rotation about a shaft  38  and connected, in turn, to the drive shaft  21  shown in  FIG. 4 , which itself is fixed for rotation with the moveably mounted platform  10 . Accordingly, upon rotation of the spur gear  31  in either direction, and by virtue of the eccentrically mounted pin  34  and link  35 , purely rotational movement of crown gear  32  is translated into an oscillating movement of drive plate  37  and hence, via drive shaft  21 , the moveably mounted platform  10 , which therefore twists back and forth about the axis of the drive shaft  21 . In doing so, floss  3   a  trapped between the clamp jaws  11 ,  13  and  12 ,  14  when the quick release clamp mechanism is in its locked position, as shown in  FIG. 2 , is pulled back and forth over the prongs  6  in consecutively opposite directions so that that portion of floss  3   a  between the prongs  6  can therefore provide for automatic flossing between teeth and over gums.  
      Although the embodiment shown with reference to FIGS.  1  to  7  is adapted to be attached to a toothbrush driver, typically comprising a battery powered electric motor and associated drive train assembly, nevertheless it will be appreciated that such, and those to be described in FIGS.  8  to  10 , may be incorporated integrally with the flosser attachment, in accordance with a second aspect of the invention.  
      As will be apparent from, particularly,  FIG. 4 , when the clamp platform  10  and associated clamp jaws  11 ,  13  and  12 ,  14  oscillate about the axis of the drive shaft  21  the length of floss  3   a  trapped therebetween immediately adjacent the clamp platform  10  oscillates to a corresponding degree. Although in the embodiment described the positioning of the platform  10  about the axis of the drive shaft  21  is perfectly symmetrical, in alternative embodiments of the invention the platform  10  may instead be positioned further forward or further back relative to the major axis of the flosser attachment to thereby vary the amount of oscillation of the floss  3   a  in this region.  
      In a further refinement, slideable clamp jaw  14  may be dimensioned to cause it to engage with fixed clamp jaw  12  just before slideable clamp jaw  13  engages with fixed clamp jaw  11  such that the captured length of floss  3   a  is provided with a degree of tension prior to the slideable jaw clamp  13  engaging with the fixed jaw clamp  11 . In an alternative embodiment, the spool of floss may be provided with a clutch mechanism to provide resistance to rotation as floss is pulled from it, thereby inherently providing a degree of tension in the captured length of floss  3   a.    
      Where the flosser attachment or electrically powered flosser, as the case may be, is not intended to be a disposable item such that replacement spools of floss may be provided, an openable cover may be provided to allow for insertion and removal of the spool as required.  
      Turning now to  FIGS. 8   a ,  8   b  and  9   a ,  9   b , there is shown an alternative quick release mechanism utilising an over-centre cam locking arrangement. A clamp platform  10   a  is again provided with fixed clamp jaws  11   a ,  12   a  and slideable clamp jaws  13   a ,  14   a , the latter pair of clamp jaws being linked via drive links  39 ,  40  to a clamp actuation plate  41  fixed for rotation about, but not with, drive shaft  21   a . The plate  41  has diagonally opposite cam surfaces  43 ,  44  which engage the innermost surfaces of the slideable clamp jaws  13   a ,  14   a , such that when the plate  41  is rotated anticlockwise in the direction arrowed by turning the knob  15   a , to which it is secured for rotation therewith, the moveable clamp jaws  13   a , l 4   a  engage the fixed clamp jaws  11   a ,  12   a  and as the knob  15   a  continues to rotate the links  39 ,  40  assume the over-centre position past centre-line c-c shown in  FIG. 8   b , in which position dental floss (not shown) is releasably secured between the clamp jaws  11   a ,  13   a  and  12   a ,  14   a.    
      As shown in  FIG. 9   b , being a part section along the line y-y of  FIG. 9   a , the slideable clamp jaw  13   a  is retained in position between the side walls  16   a ,  17   a  by being flanged at its lower end so as to be retained within corresponding recesses in the lower ends of the side walls  16   a ,  17   a  and, likewise, slideable clamp jaw  14   a  is also retained in the same manner on the opposite side of the moveably mounted platform  10   a.    
      A further embodiment of the invention is shown schematically in  FIG. 10  where a different mechanism is used to move the slideable clamp jaws  13   b ,  14   b  into and out of engagement with the fixed clamp jaws  11   b ,  12   b . In this arrangement a slotted clamp actuation disc  45  is mounted for rotation on the platform  10   b , the slots  46 ,  47  each spiralling gently outwards from the central axis of the drive shaft  21   b . The moveable clamp jaws  13   b  and  14   b  in this embodiment are each connected to respective clamp plunger rods  48 ,  49  (shown in dotted outline) received within a correspondingly shaped bore within the platform  10   a , the plunger rods  48 ,  49  having at their ends respective drive pins  50 ,  51  which extend into and engage with the inner walls of these spiral slots  46 ,  47  such that rotation of the disc  45  anticlockwise in the direction arrowed forces the plungers  48 ,  49  and hence the moveable clamp jaws  13   b ,  14   b  outwards in opposite directions towards respective fixed clamp jaws  11   b  and  12   b  at which position it will be understood that due to the length of the slots  46 ,  47  there is sufficient frictional resistance in the system to ensure that a length of floss  3   a  can be trapped therebetween until the disc  45  is rotated in the clockwise direction to release the plungers  48 ,  49  and hence moveable clamp jaws  13   b ,  14   b.    
      It will be seen that the third embodiment of the invention has relatively few moving parts which may also be relatively robust and easy to clean, as well as being relatively simply to manufacture, whether it be incorporated as part of a flosser attachment for a toothbrush driver or as part of a flosser which incorporates its own motor and drive mechanism.  
      In a still further embodiment of the invention shown with reference to FIGS.  11  to  13  the moveably mounted platform  10   c  again includes fixed clamp jaws  11   c ,  12   c  and slideable clamp jaws  13   c ,  14   c  (shown more clearly in  FIG. 12 ), the slideable clamp jaws  13   c ,  14   c , each having respective drive pins  52 ,  53  extending upwardly therefrom and being engageable in respective arcuate slots  54 ,  55  on the underside of a rotatable knob  15   b  as shown in  FIG. 13 . The slots  54 ,  55  act as cam surfaces which bear against the drive pins  52 ,  53  when the knob  15   b  is rotated to the limit imposed by a respective pair of detents  56 ,  57  in the slots  54 ,  55  such that in the position shown in  FIG. 11  the clamp mechanism shown generally at  4   a  is open and upon rotation through 90 degrees of the knob  15   b  to a position corresponding to the knob as shown in  FIG. 2  the drive pins  52 ,  53  and hence slideable clamps  13   c  and  14   c  are forced to move outwardly with respect to each other to close the locking mechanism.  
      Whilst all four embodiments of the invention thus far described are believed to offer novel and practical devices for dental flossing it will be understood that variations thereof may be possible without departing from the spirit and scope of the invention.