Abstract:
The present invention contemplates to adapt the shape and movement of a popular manual flosser into an automatic flosser to minimize the learning time required for manipulating automatic dental flossing. The present invention also contemplates to combine the automatic flosser with a popular automatic toothbrush and thus to make the automatic flosser available to the users with substantially no additional cost to the automatic toothbrush. The present invention further contemplates to accomplish circular oscillation of the toothbrush bristles of the automatic toothbrush and side-to-side vibration of the dental floss of the automatic flosser.

Description:
This application claims the benefit of U.S. provisional application No. 60/405,119, filed on Aug. 22, 2002. 

   TECHNICAL FIELD 
   The present invention relates to a motorized device and method for dental flossing and tooth-brushing. In particularly, the present invention relates to a hybrid unit of automatic dental flosser and automatic toothbrush, of which the automatic flosser drives a piece of dental floss to vibrate from side to side longitudinally while the automatic toothbrush drives the bristles to oscillate back and forth rotationally. 
   BACKGROUND 
   The clinic benefit of dental flossing is well known. If you live in the United States, the most frequent advice you may get from your dentist is to floss once a day. Traditional manual flossing is, however, time consuming and less effective. Besides, many of us find manual flossing too difficult to manipulate. 
   Automatic flosser, i.e. automatic dental flossing device, has been the subject of numerous of patents; some of them are listed as references in this application. However, automatic flossers have so far very limited acceptance in the market place. 
   There are two obvious obstacles for broad market acceptance of automatic flossers. First, substantial learning time is usually required for one to become familiar with manipulation of an automatic flosser and to see its benefit. Actually, dental flossing is never an easy job for most of us. Any new flosser or new flossing procedure will take time and practice for one to learn. 
   Second, commercially available automatic flossers are typically sold for $30 to $80 per unit in the US market. These prices are some 10 to 50 times of what one may spend for dental floss or manual flossers. Because the usefulness and benefit of a new automatic flosser are usually not obvious, not many customers are likely to pay $30 to $80 to try something new but uncertain. 
   In comparison, automatic toothbrushes have found their way to gain popularity in the past several years. Automatic toothbrushes were used to sell for some $30 to $80 per unit in the US market and had rather limited popularity. The market of automatic toothbrushes has become flourishing since Crest introduced its SpinBrush sold for about $5 each. 
   SUMMARY 
   The present invention contemplates a new and improved automatic flosser to overcome the above-identified obstacles. The present invention contemplates to adapt the shape and movement of a popular manual flosser into an automatic flosser to minimize the learning time required for manipulating automatic dental flossing. The present invention also contemplates to combine the automatic flosser with a popular automatic toothbrush and thus to make the automatic flosser available to the users with substantially no additional cost to the automatic toothbrush. The present invention further contemplates to accomplish circular oscillation of the toothbrush bristles of the automatic toothbrush and side-to-side vibration of the dental floss of the automatic flosser. 
   The combined unit of automatic flosser and toothbrush consists of a disposable floss holder, a detachable toothbrush head, and a common driving handle. This combined unit is intended to pack and sell at a price of the automatic toothbrush. Package of multiple disposable floss holders is to sell separately. This way, customers are encouraged to buy the automatic toothbrush with a free disposable floss holder and the automatic flossers become readily available for a free trial to those customers. 
   The combined unit accomplishes a circular oscillation of the toothbrush bristles, which is the most popular motion of commercially available automatic toothbrushes. Meanwhile, the combined unit accomplishes a longitudinally reciprocal movement of the dental floss, which is a more familiar motion with manual flossers. In one embodiment, the disposable floss holder remains stationary while the dental floss is moving back and forth between two tines of the automatic flosser. This design allows the dental floss to have large travel for more effective dental flossing. In another embodiment, the floss holder securing a piece of dental floss swings from side to side to move the dental floss longitudinally and reciprocally. This design enables the use of a disposable floss holder free of any moving part, and thus the disposable floss holder can be made simple and cheap. 
   The driving mechanism of the driving handle adapts designs having similar complicity to those found in popular automatic toothbrushes. The disposable floss holder can be made from a single piece of plastic using mold injection process. Therefore, the combined unit of the automatic flosser and toothbrush can be made and sold at substantially the same price as those popular automatic toothbrushes, i.e. about $5 in the US market. 
   Accordingly, an objective of the present invention is to provide a new and improved automatic dental flosser employing a disposable floss holder that stays stationary while the floss is dragged to move back-and-forth longitudinally. 
   Another objective of the present invention is to provide a new and improved automatic dental flosser employing a disposable floss holder that is made of a single piece of plastic. 
   A further objective of the present invention is to provide a new and improved automatic dental flosser sharing the same driving handle such that the combined unit of automatic flosser-toothbrush can be sold at substantially the same price of the automatic toothbrush. 
   Another further objective of the present invention is to provide a new and improved automatic flosser-toothbrush employing a hybrid motion, of which the floss holder is driven to swing side to side while the toothbrush bristles are driven to oscillate rotationally. 
   The above and other objectives and advantages of the invention will become more apparent in the following drawings, detailed description, and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows an automatic dental flosser, in accordance with the present invention. 
       FIG. 2  shows a first embodiment of a disposable floss holder. 
       FIG. 3  shows a second embodiment of a disposable floss holder. 
       FIG. 4  shows a first embodiment of a driving handle. 
       FIG. 5  shows a second embodiment of a driving handle. 
       FIG. 6  shows an automatic dental flosser with the driving shaft at different angle positions. 
       FIG. 7  shows a first embodiment of an attachable toothbrush head. 
       FIG. 8  shows an automatic toothbrush with the driving shaft at different angle positions. 
       FIG. 9  shows a third embodiment of a disposable floss holder. 
       FIG. 10  shows a second embodiment of a toothbrush head. 
       FIG. 11  shows an automatic dental flosser employing a disposable floss holder of FIG.  9 . 
       FIG. 12  shows an automatic toothbrush employing a toothbrush head of FIG.  10 . 
       FIG. 13  shows a third embodiment of a driving handle. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows an automatic dental flosser  100 , in accordance with the present invention. The automatic dental flosser  100  consists of a disposable floss holder  200  attached onto a driving handle  400 . The disposable floss holder  200  holds a loop of dental floss  210  between two tines  220  and  230 . As described below, a driving mechanism housed inside the driving handle  400  drives a driving shaft  411  to oscillate from side to side. The driving shaft  411  then drives a rotatable element  250  to swing back and forth with respect to the disposable floss holder  200 . As a result, the loop of dental floss  210  is drag to slide back and forth between the two tines  220  and  230  for dental flossing, while the disposable floss holder  200  stays stationary with respect to the driving handle  400 . 
     FIG. 2  shows a first embodiment of a disposable floss holder  200 , in accordance with the present invention. The disposable floss holder  200  is shown in front, side, and back view. The disposable floss holder  200  consists of a holder body  201 , a rotatable element  250 , and a loop of dental floss  210 . The rotatable element  250  is rotatable with respect to the holder body  201  via a pin-and-hole structure  251 . 
   One point  255  of the rotatable element  250  is tied to the loop of dental floss  210 . The rotatable element  250  is affixed with an engagement element  254  that has a notch  253 , which can be engaged with the tip of a driving shaft  411  from the driver handle  400 , as shown in FIG.  1 . There is an opening  256  on the holder body  201  to receive the engagement element  254  and to allow the engagement element  254  to rotate within a range around the pin-and-hole structure  251 . As the driving shaft  411  of the driving handle  400  oscillates from side to side, it drives the rotatable element  250  to swing back and forth with respect to the holder body  201 . 
   The pin-and-hole structure  251  has two possible configurations. The first configuration is to have a hole on the holder body  201  and a pin on the rotatable element  250  to insert into the hole. The other configuration is to have a pin on the holder body  201  and a hole on the rotatable element  250  to receive the pin. This way the rotatable element  250  is rotatable around the pin-and-hole structure  251 . 
   The loop of dental floss  210  is held between the two tines  220  and  230  through holding slots  202 ,  203 ,  207 , and  206 . The loop of dental floss  210  is free to slide back and forth around these holding slots  202 ,  203 ,  207  and  206 . When the rotatable element  250  swings back and forth around the pin-and-hole structure  251 , it drags the loop of dental floss  210  to move back and forth between the two tines  220  and  230 . 
   The implement of the rotatable element  250  with the engagement element  254  is for two advantages. First, it can enlarge the travel of the dental floss  210  between the two tines  220  and  230 , in comparison with the displacement of the driving shaft  411 . Second, it provides a simple engagement to transfer the oscillation of the driving shaft  411  to the back-and-forth movement of the dental floss  210  with the floss holder remaining stationary. Preferably, the first end  412  of the driving shaft  411  has a peak-to-peak oscillation of approximately 2 to 3 mm and the dental floss  410  has a back-and-forth travel of about 4 to 8 mm. 
   There is a mounting hole  240  on the second end of the holder body  201 . This hole  240  is used to attach and to secure the floss holder  200  onto the driving handle  400 . There is also a hole  241  connecting between the mounting hole  240  and the opening  256 . As shown in  FIG. 1 , this hole  241  enables the driving shaft  411  of driving handle  400  to engage with the notch  253  of the engagement element  254  and thus to drive the rotatable element  250  to swing back and forth around the pin-and-hole structure  251 . 
     FIG. 3  shows a second embodiment of a disposable floss holder  300 , in accordance with the present invention. The disposable floss holder  300  is shown in front, side, and back view. This disposable floss holder  300  has similar structure as the disposable floss holder  200  except that the pin-and-hole structure  251  is replaced with a narrow bridge structure  351  and the rotatable element  350  is modified from the rotatable element  250  accordingly. The rotatable element  350  is connected and rotatable with respect to the holder body  301  via this narrow bridge structure  351 . 
   The material chosen for the disposable floss holder  300  shall be durable for bending back and forth over such a narrow bridge structure  351 . Materials suitable for this purpose are known to those skilled in the art. 
   As shown in  FIG. 3 , the rotatable element  350  is coupled with an engagement element  354  that has a notch  353  to engage with the driving shaft  411 . An opening  356  on the holder body  301  receives the engagement element  354  and allows the engagement element  354  to swing within a range with respect to the narrow bridge structure  351 . 
   The holder body  301  with the rotatable element  350  can then be made with a single piece of plastic through mold injection process. Such a design simplifies the production process and reduces the production cost. As a result, the floss holder  300  can be better justified as a disposable item. 
     FIG. 4  shows a first embodiment of a driving handle  400  of the automatic dental flosser  100 , in accordance with the present invention. The driving handle  400  consists of a handle body  440  and a driving shaft  411 . The handle body  440  houses a motor  420 , a driving mechanism, and a battery or charger that is not shown in the Figure. The handle body  440  has an elongate shape and is such shaped to allow the user to grasp comfortably for dental flossing. The first end  441  of the handle body  440  is sized to fit into the hole  240  of the disposable floss holder  200 . The first end  412  of the driving shaft  411  is shaped to fit with the notch  253  of the engagement element  254  of the disposable floss holder  200 . In operation, the driving shaft  411  oscillates from side to side to drive the rotatable element  250  to swing back and forth with respect to the holder body  201  and to drag the loop of dental floss  210  to slide back and forth between the two tines  220  and  230 . 
   As shown in  FIG. 4 , the driving mechanism includes a gear  421 , a wheel  430 , and a bar  419 . The motor  420  drives the gear  421 , which is coupled to the wheel  430  rotating around a shaft  431 . The power coupling is through a layer of deformable material  436 , e.g. rubber or soft plastic. Such a design is for its simplicity and low noise in comparison with typical gear coupling. The wheel  430  is concentric and affixed with a smaller wheel  432 . A pin  437  is mounted on the smaller wheel  432  with an offset from the wheel&#39;s center, i.e., the shaft  431 . 
   The bar  419  has a slot  418  at its first end and extends to the driving shaft  411  at its second end. The slot  418  is engaged into the pin  437  of the wheel  432 . As the wheel  432  rotates, the pin  437  drives the bar  419  to swing back and forth around a pin  413 , which is affixed on the handle body  440 . Consequently, the bar  419  transfers the continuous rotation of the wheel  430  to a side-to-side oscillation of the driving shaft  411 . 
   Preferably, the rotation speed of motor  420 , the size of the gear  421 , and the size of the wheel  430  are such chosen that the oscillation rate of the driving shaft  411  is about 30 to 50 Hz. The length of the driving shaft  411 , the length of the bar  419 , and the offset of pin  437  are such designed that the tip  412  of the driving shaft  411  has a side-to-side travel of about 2 to 3 mm. 
     FIG. 5  shows a second embodiment of a driving handle  500  of the automatic dental flosser  100 , in accordance with the present invention. The construction of the driving handle  500  is similar to that of the driving handle  400  except the driving mechanism that couples the continuous rotation of the motor  520  to the side-to-side oscillation of the driving shaft  511 . 
   As shown in  FIG. 5 , the driving mechanism includes a first disk  521 , a second disk  531 , and a bar  519 . The first disk  521  is affixed on the motor&#39;s shaft and is mounted with an off-center pin  522 . The second disk  531  is affixed on a first end of the bar  519  and is embedded a slot  532 . 
   The motor  520  rotates the first disk  521  continuously. The off-center pin  522  slides inside the slot  532  and pushes the bar  519  to swing back and forth around a pin  513 . Consequently, the driving mechanism transfers the continuous rotation of the motor  520  to a side-to-side oscillation of the driving shaft  511 . 
   Preferably, the rotation speed of motor  520  is such chosen that the oscillation rate of the driving shaft  511  is about 50 to 100 Hz. The length of the driving shaft  511 , the length of the bar  519 , and the offset of pin  522  are such designed that the tip  512  of the driving shaft  511  has a side-to-side travel of about 2 to 3 mm. 
     FIG. 6  shows an automatic dental flosser  600  with the driving shaft  411  at different angle positions. The automatic dental flosser  600  is shown in a back view of the floss holder  200 . The driving shaft  411  is engaged with the notch  253  on the engagement element  254 . As the driving shaft  411  oscillates from side to side, it drives the engagement element  254  and thus the rotatable element  250  to swing back and forth with respect to the floss holder  200 . The rotatable element  250  drives in turn the loop of dental floss  210  to slide back and forth between the two tines  220  and  230 . 
   The size of the rotatable element  250  and the distance from the notch  253  to the rotation center  251  shall be such chosen that the dental floss  210  has a side-to-side travel of about 4 to 8 mm. 
     FIG. 7  shows a first embodiment of a toothbrush head  700 , in accordance with the present invention. The toothbrush head  700  is shown in front, side, and back view. The toothbrush head  700  consists of a toothbrush head body  701  and a rotatable bristle holder  750 . Toothbrush bristles  730  are implanted on the rotatable bristle holder  750 , which is in turn mounted on the first end of the toothbrush head body  701  and is operationally rotatable around a pin-and-hole structure  751 . 
   As shown in the back view of the toothbrush head  700 , the rotatable bristle holder  750  is affixed with an engagement element  754 , which has a notch  753  to engage with the driving shaft  411 . There is an opening  756  on the toothbrush head body  701  to receive the engagement element  754  and to allow the engagement element  754  to rotate within a range around the pin-and-hole structure  751 . 
   There is a mounting hole  740  in the second end of the toothbrush head body  701 . This hole  740  is used to attach the toothbrush head  700  onto the driving handle  400 . There is also a hole  741  connecting between the mounting hole  740  and the opening  754 . This hole  741  enables the driving shaft  411  of driving handle  400  to engage with the notch  753  of the engagement element  754  so as to drive the rotatable bristle holder  750 . When the rotatable bristle holder  750  is driven to rotate back and forth around the pin-and-hole structure  751 , the bristles  730  wipes back and forth for tooth brushing. 
     FIG. 8  shows an automatic toothbrush  800  with a toothbrush head  700  at different angle positions of the driving shaft  411 . The automatic toothbrush  800  is shown in a front view of the toothbrush head  700 . The driving shaft  411  is engaged with the notch  753  on the engagement element  754 . As the driving shaft  411  oscillates from side to side, it drives the rotatable bristle holder  750  to rotate and thus the bristles  730  to wipe back and forth for tooth brushing. 
   The size of the rotatable disk  750  and the distance from the notch  753  to the rotation center  751  shall be such chosen that the toothbrush bristles  730  have a back and forth travel distance up to 4 to 8 mm. 
     FIG. 9  shows a third embodiment of a disposable floss holder  900 , in accordance with the present invention. The floss holder  900  has on its first end two tines  920  and  930  securing a piece of dental floss  910  and on its second end a mounting hole  940 . The two tines  920  and  930  are such shaped and bent to hold the piece of dental floss  910  perpendicular to and about 5 to 20 mm away from an axis  942  of the mounting hole  940 . The two tines  920  and  930  are further bent and spaced to have the piece of dental floss  910  a length of about 10 to 20 mm. The mounting hole  1040  is sized to fit the driving shaft  411  of the driving handle  400 . 
     FIG. 11  shows an automatic dental flosser  1100  with a disposable floss holder  900 , in accordance with the present invention. The automatic dental flosser  1100  consists of a disposable floss holder  900  fastened onto the driving shaft  411  of a driving handle  400 . As the driving shaft  411  swings from side to side around the pin  413 , the floss holder  900  moves back and forth for dental flossing. 
   The length of the disposable floss holder  900  is chosen such that the travel distance of the floss  910  is up to preferably 4 to 6 mm. For a preferred embodiment, the peak-to-peak oscillation amplitude of the tip  412  of the driving shaft  411  is about 2 to 3 mm and the length of the driving shaft  411  is about 40 mm, the length of the disposable floss holder  900  is approximately 50 mm. 
     FIG. 10  shows a second embodiment of an attachable toothbrush head  1000 , in accordance with the present invention. The toothbrush head  1000  has bristles  1030  implanted on its first end and a mounting hole  1040  on its second end. The mounting hole  1040  is sized to fit the driving shaft  411  of the driving handle  400 . 
     FIG. 12  shows an automatic toothbrush with a toothbrush head  1000 , in accordance with the present invention. The automatic toothbrush  1200  consists of a detachable toothbrush head  1000  fastened onto the driving shaft  411  of a driving handle  400 . As the driving shaft  411  swings from side to side around the pin  413 , the toothbrush head  1000  wipes back and forth for tooth brushing. 
   The length of the detachable toothbrush head  1000  is such chosen that the travel distance of the toothbrush bristles  1030  is preferably 4 to 6 mm. For a preferred embodiment, the peak-to-peak oscillation amplitude of the tip  412  of the driving shaft  411  is about 2 to 3 mm and the length of the driving shaft  411  is about 40 mm, the length of the detachable toothbrush head  1000  is approximately 50 mm. 
   The floss holder  900 , as well as the floss holders  200  and  300 , adapts the shape of the tines from a popular manual floss holder that is relatively easy to manipulate. The floss holder  900  is simple and easy to make, and it is thus better justified to be a disposable item. 
   The automatic toothbrush  800  adapts a circular oscillation of the toothbrush bristles  730 . Such a circular oscillation has been well accepted in the market. 
   The driving handles  400  and  500  implement a side-to-side oscillation of the driving shaft to enable the automatic dental flossers  100  and  1100  and automatic toothbrushes  800  and  1200 . Any combination of these automatic dental flossers and toothbrushes can be a useful product. 
   It is understood that floss holder  200  and toothbrush head  700  adapt a similar circular oscillation of a rotatable member. Therefore, other driving mechanism or coupling mechanism that can provide a circular oscillation to a toothbrush head can also be used to drive a floss holder with a rotatable element. 
   It is also understood that dental flosser  1100  and toothbrush  800  adapt a hybrid motion, of which the floss holder is driven to swing side to side while the toothbrush bristles are driven to oscillate rotationally. Other than the driving shafts and driving mechanisms described in  FIGS. 4 and 5 , there are driving mechanisms that can provide similar hybrid motion or provide movements including such a hybrid motion. 
   For example,  FIG. 13  shows a third embodiment of a driving handle  1300  that is suitable to provide a hybrid motion for dental flossing and tooth brushing, in accordance with the present invention. The construction of the driving handle  1300  is similar to that of the driving handle  400  except the driving mechanism that couples the continuous rotation of the motor  1320  to a side-to-side swing oscillation of the driving shaft  1311 . 
   As shown in  FIG. 13 , the driving mechanism includes a disk element  1321 , an arm element  1331 , and a bar  1319 . The disk  1321  is affixed on the motor&#39;s shaft and is mounted with an off-center pin  1322 . The arm element  1331  is affixed on a first end of the bar  1319  and is embedded a slot  1332 . The motor  1320  rotates the disk element  1321  continuously. The off-center pin  1322  slides inside the slot  1332  and pushes the bar  1319  to rotate back and forth around a bearing  1313 . Consequently, the driving mechanism transfers the continuous rotation of the motor  1320  to a rotational oscillation of the driving shaft  1311  around an axis  1315 . 
   When a floss holder  900  is fastened on the driving shaft  1311 , the driving handle  1300  can drive the floss holder  900  to swing from side to side around an axis  1315  of the driving handle  1300 . When a toothbrush head  700  is attached onto the driving handle  1300 , the driving shaft  1311  can drive the toothbrush bristles  730  to oscillate rotationally with respect to the toothbrush head  700 . Consequently, the driving handle  1300  provides a hybrid motion for dental flossing and tooth brushing. 
   Therefore, it is further understood that, the present disclosure includes only a few embodiments, other modifications and variations may be made without departing from the following claims.