Abstract:
A hand-held dental floss holder, dispenser, floss tensioning, and floss advancing device. The device is configured with one end being a handle and the other being a pair of tips across which dental floss is spanned for presenting to inter-dental spaces. An internal supply of dental floss is housed inside the handle. The floss passes from the supply, moves around floss guides, wraps one or more times around a free spooling clutch spool, exits the body of the device through an opening and is directed to and across the tips of the device and is guided back to a collection spool rotationally connected to a manually-activated one way thumbwheel. In a first position, the gearing of a gear assembly and an internal clutch spool assembly causes the floss to tension when the thumbwheel is turned. In a second position, the disengagement of gearing allows the clutch spool to spool freely, allowing fresh floss to be substituted for used floss, when the thumbwheel is turned.

Description:
TECHNICAL FIELD 
   The present invention relates to devices for easing the chore of flossing with dental floss, and more particularly relates to hand-held devices which dispense and tension fresh dental floss for use by a user, and which concurrently spool used dental floss. 
   BACKGROUND 
   Daily flossing is an integral part of a complete oral hygiene program. Brushing one&#39;s teeth without flossing leaves a large portion of the tooth surfaces uncleaned. Flossing helps to remove harmful plaque and bacteria from between teeth, where a toothbrush can&#39;t reach. It is well known that plaque build-up can lead to gum disease, chronic bad breath, tooth loss and other ailments. Even with these risks, most adults do not floss on a regular basis. 
   This is largely because traditional flossing methods are awkward, difficult and painful to many people, causing them to skip the important step of flossing. Apart from mere laziness, there are other reasons people don&#39;t floss. These include spatial interference (when one&#39;s hands are too large to properly manipulate floss within one&#39;s mouth, or when an adult, for example, is attempting to floss a child&#39;s teeth), loss of circulation (floss wrapped tightly around a fingertip cuts off circulation to the tip of the finger, a painful and unpleasant situation), disability (arthritis or any other disability affecting manual dexterity can limit or prevent the proper manipulation of floss), and the general unhygienic nature of the process (hands are in contact with used floss, and must be placed repeatedly deep within the mouth). Flossing is also simply generally inconvenient, requiring concentration, the use of two hands at all times, and time to prepare a new section of floss for each tooth. 
   To ease the inconvenience of flossing, a large variety of flossing devices have been suggested, among them those disclosed in the following U.S. Pat. Nos. 3,734,107, 5,038,806, 5,819,769 5,823,207, 6,161,556, and also in U.S. patent application No. US2002/0170570. 
   All of these prior art dental floss systems have disadvantages that keep them from being commonly used. Some are very complicated in structure and expensive to produce. Some do not permit the easy substitution of new floss for used floss. Some require two hands to operate. There remains, accordingly, a need for a relatively simple dental floss dispensing device that is easily operated with one hand. 
   SUMMARY OF INVENTION 
   The present invention is a dental floss dispensing device which has a thumbwheel for operation by a single thumb or finger, to allow a user to dispense floss, hold, advance and properly tension it, and to collect used floss. 
   The device, in a preferred embodiment, is hand-held and has a handle portion having a semi-hollow interior. Attached to or formed at one end of the handle portion is a flossing portion bearing a pair of arms for supporting between them a length of dental floss for insertion by a user between a pair of teeth. 
   Within the interior of the handle portion are contained, at least partially, two geared assemblies, a “gear assembly” and a “clutch spool assembly”. The gear assembly is fixed within notches formed in the handle portion, and has an axle supported by the handle portion. The axle bears a thumbwheel for turning the axle, a used-floss collection spool, and an axle gear, with at least the axle gear being contained within the interior of the handle portion. The clutch spool assembly is completely supported and contained within the interior of the handle portion, and comprises a clutch spool having a clutch gear attached to one side thereof. 
   When a length of floss is threaded in the device from a spool of floss contained within the interior of the handle portion to and around the clutch spool, and then from the clutch spool out of the body of the device to a tip of one of the arms (the first arm), then from the first arm to the second arm, and then from the second arm to the used-floss collection spool, the gear assembly is manipulable by manipulating the thumbwheel into a first position wherein the axle gear of the gear assembly is engaged with the clutch gear of the clutch spool assembly, thereby tensioning the floss between the arms of the flossing portion by causing the collection spool and the clutch spool to turn in opposite directions when the thumbwheel is turned in a first direction. The thumbwheel may be prevented from being turned in the other direction by a pawl acting on ridges or grooves formed on the circumference or face or side of the thumbwheel. 
   So, while the thumbwheel is in a position wherein the axle gear and clutch gear are engaged, floss becomes tensioned and cannot move through the device. However, the gear assembly may also be manipulated by manipulating the thumbwheel into a second position wherein the axle gear is disengaged with the clutch gear of the clutch spool assembly. This allows the clutch gear to spool freely in the same direction as the collection spool, allowing at least a portion of the length of floss to be taken up onto the collection spool, and a fresh portion of floss to be advanced onto and suspended between the arms of the device. 
   In the preferred embodiment, the gear assembly is normally urged into the first, engaged position by springs applying force to the axle. 
   Used floss is taken up on an externally mounted collection spool. For sanitary and hygienic purposes used floss can be easily removed after each use. A cutter is included for this purpose. The collection wheel and all surfaces that make contact with the used floss are fully accessible for easy cleaning and disinfecting. No contact of the floss by the user&#39;s hands is required other than to cut and dispose of the used floss after flossing. The device is disposable or may be reused. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     It will be appreciated that the particularized description of the invention described briefly above and which follows hereafter is rendered by reference to certain specific embodiments of the invention which are illustrated in the appended drawings. The drawings depict only one typical embodiment of the invention and are not therefore to be considered to be limiting of the scope of the invention. 
     Accordingly, in the accompanying drawings which illustrate a specific embodiment of the invention, but which should not be construed as restricting the spirit or scope of the invention in any way: 
       FIG. 1  is a top perspective view of a flossing device made in accordance with one embodiment of the present invention. 
       FIG. 2  is bottom perspective view of the flossing device shown in  FIG. 1 . 
       FIG. 3  is a perspective view of the bottom portion of the flossing device shown in  FIG. 1 , showing the interior of the bottom portion. 
       FIG. 4  is a perspective view of the top portion of the flossing device shown in  FIG. 1 , showing the interior of the top portion of the device. 
       FIG. 5  is a perspective view of the bottom portion of the flossing device as shown in  FIG. 3 , showing a spool of floss, the gear assembly and the clutch spool assembly of the device in place, and showing floss extending from the floss spool to the floss collection spool. 
       FIG. 6  is a perspective view of the top portion of the flossing device as shown in  FIG. 4 , showing the gear assembly of the device as it would occupy space in the top portion when in place. 
       FIG. 7  is a perspective view of the gear assembly of the present device shown in  FIG. 1 . 
       FIG. 8  is a partially schematic cross-sectional view of the gear assembly and clutch spool assembly of the device shown in  FIG. 1 , taken in cross section along line A—A shown in  FIG. 5 , with the gear assembly urged into an engaged position wherein it is in geared engagement with the clutch spool assembly. 
       FIG. 9  is a partially schematic cross-sectional view of the gear assembly and clutch spool assembly of the device shown in  FIG. 1 , looked at end-on, generally along line A—A shown in  FIG. 5 , similar to the view shown in  FIG. 8 , but with the gear assembly forced downwardly so that it in an unengaged position. 
       FIG. 10  is a side view of the clutch spool assembly of the device shown in the Figures. 
       FIG. 11  is a perspective view of the clutch spool assembly shown in  FIG. 10 . 
   

   DESCRIPTION 
   Throughout the following description, specific details are set forth in order to provide a more thorough understanding of the invention. However, the invention may be practiced without these particulars. In other instances, well known elements have not been shown or described in detail to avoid unnecessarily obscuring the invention. Accordingly, the specification and drawings are to be regarded in an illustrative, rather than a restrictive, sense. 
   Referring first to  FIG. 1 , the present invention provides a device which dispenses, holds, tensions, collects and cuts dental floss for use by a user. The flossing device, referred to generally herein by reference numeral “ 10 ” has, generally, a handle portion  12  for allowing a user to hold and manipulate the device, and a flossing portion  14  for insertion into the mouth of a user to floss between the user&#39;s teeth. The handle portion  12  may be of any suitable size or shape which allows the device to contain a spool of floss and the gear assembly and clutch spool assembly of the invention as described below. 
   As shown in  FIG. 1 , in a preferred embodiment of the invention the flossing portion  14  of device  10  ends in a pair of arms, first arm  16 A and second arm  16 B. Arms  16 A,  16 B are intended to support a usable length of dental floss between them, as described further below. 
     FIG. 2  shows the underside of device  10 . It will be appreciated that it may be convenient for device  10  to be able to be opened by a user to replace an empty spool of floss within the device  10 . To this end, it is proposed in the illustrated embodiment of the invention that the handle portion  12  of device  10  be constructed of a bottom portion  70  and a top portion  80 , as shown more clearly respectively in  FIGS. 3 and 4 . The top and bottom portions  80 ,  70  of handle portion  12  may be attached to one another with screws  26  ( FIG. 2 ) which pass through screw bosses  25  ( FIGS. 3 and 4 ) on the inside of one or both of the top or bottom portions  80 ,  70  of handle portion  12 . Of course, it is not necessary to the invention that the device  10  be openable, as it is foreseen that disposable versions of the device could be manufactured. 
   As shown in  FIG. 5 , the device  10  is configured to house a spool of floss  20 . Of course, it is not necessary for the floss to be supplied on a spool, but this preferred arrangement is shown in the drawings. In the preferred embodiment, spool  20  is supported by front and rear spool supports  18 A,  18 B,  19 A and  19 B (seen in  FIGS. 3 and 4 ). A wall  22 A,  22 B may be provided within the device  10  to totally enclose spool  20 . If this wall is provided, then a slot  23  must also be provided to allow a strand of floss to pass through the wall from the spool  20 . As is typical with other hand-held flossing devices, a strand of floss  24  may be directed from the spool  20  to first arm  16 A, then across to second arm  16 B and then to a collection spool  36 . The usable portion of floss  24  is the portion supported between arms  16 A and  16 B. “Fresh” floss is therefore dispensed from spool  20 , and “used” floss collected on collection spool  36 . 
   As will be appreciated, however, if the strand of floss  24  is not tensioned between arms  16 A and  16 B, it will be too limp to be usable by a user. So, it is an object of the invention to provide means for tensioning the floss  24  for a period of time for use by a user by not allowing fresh floss to spool “forward” from spool  20 , and concurrently by not allowing used floss which has already been spooled onto collection spool  36  to return “backwards” towards arms  16 A,  16 B. 
   This is accomplished in the present invention by an ingenious combination of two geared assemblies contained at least partially within the device  10 .  FIGS. 7 and 11  provide perspective views of the two geared assemblies of the invention. 
   As shown in detail in  FIG. 7 , the device  10  has a gear assembly  30  which has an axle  34 . Axle  34  bears upon it a thumbwheel  32  for allowing a user to turn the assembly  30  when it is contained in place within device  10 . Axle  34  also bears upon it the collection spool  36  previously described. Also borne on axle  34  is what is hereafter termed an “axle gear”  38 , which in a preferred embodiment is located at or near thumbwheel  32 . 
   As shown in  FIG. 11 , the device also has what is termed herein a “clutch spool assembly”  40 . Clutch spool assembly  40  has a clutch spool  42  having attached to one side thereof a clutch gear  44 . Clutch spool assembly  40  is also shown in side view in  FIG. 10 . Clutch gear  44  has gear teeth which are sized and configured to mate with the gear teeth of axle gear  38  of gear assembly  30 . Clutch spool assembly  40  may have a bore  45  formed therethrough to allow assembly  40  to be held in place within device  10 . 
   The top and bottom portions  80 ,  70  of device  10  are configured to accept and hold in place gear assembly  30  and clutch spool assembly  40 . For example, as shown in  FIGS. 3 and 4 , each one of the bottom and top portions  70 ,  80  of device  10  has a rectangular opening formed therethrough, for allowing thumbwheel  32  of gear assembly to protrude therethrough when gear assembly is in place within the device.  FIG. 1  illustrates how thumbwheel  32  protrudes through the top portion  80  of device  10 , and  FIG. 2  shows thumbwheel  32  protruding through the bottom portion  70  of device  10 . 
   It will be appreciated from the figures that axle  34  of gear assembly  30  is held in place and supported at least partially by the side walls of the top and bottom portions  80 ,  70  of handle  12  of device  10 . As shown in  FIG. 3 , the bottom portion  70  of handle  12  has oblong notches  52  formed in the sides thereof. Similarly, the top portion  80  of handle  12  has semicircular notches  54  formed in the sides thereof ( FIG. 4 ). Notches  52  and  54  face one another when the top and bottom portions  80 ,  70  are connected by screws  26 . 
   As shown in  FIG. 5 , gear assembly  30  is contained within device  10  by fitting axle  34  within notches  52  and  54 , with the notches  52 ,  54  able to act as bearings for axle  34 . Thumbwheel  32  is contained within device  10  (but for the portions which protrude from the top and bottom portions of handle  12 ), as is axle gear  38 . Collection spool  36  is preferably outside of the device, but may be alternatively enclosed within the device. Axle  34  can also be seen to be supported by the walls of the handle  12  in  FIG. 2 . 
   In the preferred embodiment shown in the figures, the clutch spool assembly  40  is also fitted within the handle  12  of the device  10  so that clutch gear  44  is capable of mating with axle gear  38 , as shown in  FIGS. 5 and 6 . This is conveniently accomplished by providing a shaft  46  ( FIG. 4 ) on the side wall of the top portion  80  of handle  12 . The bore  45  of clutch spool assembly  40  is suitably sized to allow clutch spool assembly  40  to fit onto shaft  46  and to rotate freely thereon. 
   As shown in  FIG. 5 , in operation a strand of floss is taken from spool  20 , and wound once or more times around clutch spool  42 . From clutch spool  42 , the strand of floss extends forwardly and exits handle  12  to the flossing potion  14  of device  10 . Floss  24  is then passed to the tip or near to the tip of first arm  16 A, across to the tip of arm  16 B, and from arm  16 B to collection spool  36 . Collection spool  36  may have a cutting device  37  ( FIG. 7 ) mounted or formed thereon for cutting floss  24 . Cutting device  37  may also be mounted upon handle portion  12  or flossing portion  14 . One or more guides  27  may assist in directing the path of the floss. 
   The engagement relationship between gear assembly  40  and clutch spool assembly  40  is illustrated in  FIGS. 8 and 9 . 
   In a first position, shown in  FIG. 8 , the axle gear  38  of gear assembly  30  and the clutch gear  44  of clutch spool assembly  40  engage one another, so that when one of gear assembly  30  and clutch spool assembly  40  is turned, the other assembly turns also, but in the opposite direction. In the preferred embodiment of the invention, springs  50  ( FIG. 3 ) normally urge gear assembly  30  into this engaged position with clutch spool assembly  40 . As shown in  FIG. 5 , when in this engaged position, if thumbwheel  32  is turned forwardly by a user in a direction “F”, this causes collection spool  36  and axle gear  38  to turn in the same direction “F”. However, the turning of axle gear in direction “F” causes the clutch gear  44  to turn in the opposite direction, “R”. It will thus be appreciated that if there is enough frictional force between the floss  24  and the surface of clutch spool  42 , and also between the floss  24  and the surface of collection spool  36 , the turning of the thumbwheel  32  will tend to cause floss  24  to be pulled forwardly onto collection spool  36  and also backwardly onto clutch spool  42 , thereby tensioning floss  24 . The frictional force exerted by the floss can be increased by constructing the outer surface of the clutch spool of a material with sufficient surface frictional coefficient to prevent floss from slipping under tension when wrapped once around said clutch spool. Or, the floss can be wrapped two or three times around the spool to ensure enough friction. 
   So, a length of floss having the foregoing discussed arrangement within device  10  can be tensioned by turning the thumbwheel of the device forwardly. However, it is also necessary to supply a new supply of floss between the arms  16 A and  16 B from time to time, and to collect used floss onto collection spool  36 . This is accomplished by disengaging gear assembly  30  from clutch spool assembly  40 . 
   As shown in  FIG. 9 , this is accomplished in the device  10  by pushing gear assembly  30  downwardly in the direction “D” against the force exerted by springs  50  and then turning thumbwheel  32 . It will be appreciated that the oblong nature of notches  52  allows for axle  34  of gear assembly  30  to move downwardly into notches  52 . Again considering  FIG. 5 , when in this disengaged position, the turning of gear assembly  30  in the direction “F” causes collection spool  36  and axle gear  38  to turn in the same direction “F”. However, in this position, axle gear  38  is not engaged with clutch gear  44  and accordingly does not force clutch gear  44  to turn in the opposite direction, “R”. Rather, clutch assembly  40  spools freely in direction F, and fresh floss  24  is passed from spool  20 , around clutch spool  42 , and to arms  16 A,  16 B. Once fresh floss passes to between arms  16 A and  16 B, the user releases pressure on thumbwheel  32 , allowing the engagement of gears  38  and  44 , thereby permitting the tensioning of floss by turning thumbwheel  32 , as previously discussed. 
   It will be recognized that to maintain the floss in a tensioned state it is necessary not to allow thumbwheel  32  to turn “backwards” in the direction “R”. While the user could accomplish this by maintaining “forward” pressure on thumbwheel  32 , it is convenient to provide a pawl  60  ( FIG. 4 ) to act on teeth or ridges  62  formed on thumbwheel  32 . Conveniently, ridges  62  on thumbwheel  32  also serve to provide a user with a better grip on thumbwheel  32 . 
   It will be appreciated that what is important to the invention is the interaction between gear assembly  30  and clutch assembly  40 . The particular path taken by floss  24  is not vital to the invention. Accordingly, it is recognized that floss  24  could pass entirely through the device  10  to the tip of arm  16 A. Similarly, although the Figures show floss  24  being threaded through holes formed in the tips of arms  16 A,  16 B, the floss could simply be held on arms  16 A  16 B in grooves formed at the tips of the arms. 
   As will be apparent to those skilled in the art in the light of the foregoing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. For example, although the embodiment of the invention shown in the drawings has screws  26  attaching top and bottom portions  80 ,  70  to one another, snapping tabs could be used in their place. 
   Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.