Patent Publication Number: US-7219384-B2

Title: Powered toothbrush

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This is a continuation of U.S. application Ser. No. 11/079,325, filed Mar. 14, 2005, now U.S. Pat. No. 7,007,332, which is a continuation of application PCT/US2003/28335, filed Sep. 9, 2003, which claims the benefit of U.S. Provisional Application 60/410,078 filed Sep. 12, 2002, all of which are incorporated herein by reference in their entirety. 

   BACKGROUND OF THE INVENTION 
   As toothbrush design has evolved in an effort to improve cleaning of teeth and gums, the complexity of toothbrushes and their functions have increased. Powered toothbrushes are one example of efforts to improve tooth cleaning by including one or more movable sets of cleaning elements. Another approach to improving cleansing of teeth is use of a toothbrush head that is articulated or segmented to better follow the rounded curvature of teeth aligned in the human jaw. 
   However, little has been done to synergistically combine these approaches in a manner that achieves effective cleaning of all teeth while carefully avoiding harm to the gum line. That is an object of this invention. 
   One approach to a segmented or articulated toothbrush head is shown in U.S. Pat. No. 6,314,606B1 issued Nov. 13, 2001 to Douglas Hohlbein. This patent disclosed a two part toothbrush head joined by a living hinge or other integrally molded elastomeric-type connector. Under one embodiment of this patent, the part of the toothbrush head most remote from the handle is normally angled with respect to the head section nearest the handle. According to the patent, the flexible angulation of the head accommodates to the curvature of the human jaw, as well as the relatively straight portions of the jaw. In addition, the flexibility of at least a portion of the head provides a more gentle treatment of the gum line because the force applied by the user is moderated and more evenly distributed through the hinge (column 1, lines 61–67). 
   SUMMARY OF THE INVENTION 
   A powered toothbrush is disclosed which drives a moving portion of the toothbrush head in a reciprocal motion about a hinge joining the moving portion of the head to a fixed portion of the head. The reciprocation movement provides a power assisted tip pulsing action. 
   To facilitate this movement, the living hinge construction used in the aforementioned patent may be replaced with a less rigid hinge such as a pivoting pin and socket joint. However, the hinge construction may be of any type that does not affect the powered reciprocating of the moving portion of the toothbrush head. 
   The movable section of the toothbrush head can be powered by using the type of drive mechanism shown in U.S. Pat. No. 5,625,916. 
   Another powered toothbrush is described in U.S. Pat. No. 6,347,425B1 issued Feb. 19, 2002 and assigned to the assignee of this invention. It discloses an electrically powered toothbrush having rotatable drive shaft with an end off-set from the central longitudinal axis of the drive shaft which provides a reciprocating, rocking motion to a set of cleaning elements. 
   In a preferred embodiment, the movable portion of the toothbrush head has a flange extending therefrom toward the handle. This flange preferably has a horizontal slot that accepts an offset in a drive shaft extending from the motive source in the toothbrush handle for example, a motor. This offset in the drive shaft is similar to that shown in U.S. Pat. No. 6,347,425B1 discussed above. 
   The slot in the flange interacts with the offset in the drive shaft to form a “slip clutch” so that if an excessive load is applied to the movable portion of the toothbrush head, the motor powering the toothbrush will not stall. This “slip clutch” effect also has the advantage of being a safety mechanism when in use. More particularly, the slip clutch limits operation of the movable portion of the head if the user applies excessive force to the handle. 
   The use of the flange extending from the powered portion of the toothbrush head also permits a low profile of the toothbrush head. That low, compact profile facilitates insertion and use of the toothbrush in the human mouth. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     This invention is capable of use in a broad array of consumer packaging and products. The drawings illustrate one use of the invention and are not to be construed as the only embodiment of the invention. 
       FIG. 1  is a perspective view of a power toothbrush with a power driven movable portion of a toothbrush head. 
       FIG. 2  is an enlarged cross-sectional view showing the movable portion of the toothbrush head with attached flange powered by an offset drive mechanism, in one position. 
       FIG. 3  is an enlarged cross-sectional view showing the movable portion of the toothbrush in another position. 
       FIG. 4  is an elevational view showing the slot in a tab on the flange attached to the movable portion of the toothbrush head in alternate positions. 
       FIG. 5  is an elevational view showing an alternate design of the slot on the tab attached to the movable portion of the toothbrush head. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   The powered toothbrush  10  of this invention includes a motor  12  powered by batteries or rechargeable energy source  14 . The toothbrush  10  can be operated by depressing or otherwise operating power switch  16  on the body of toothbrush  10 . 
   A powered motor  12  rotates in a conventional manner. A drive shaft  18  is connected to the motor  12  through a shaft coupling or other means of directly transferring the motor&#39;s rotation to drive shaft  18 . 
   Toothbrush  10  contains a two part articulated head  20  comprising a movable portion  22  and stationary portion  24  formed as part of the overall powered toothbrush. Movable portion  22  preferably has a soft elastomeric coating  23  which reduces the impact thereof on the users teeth and mouth during use. These portions of head  20  are preferably joined by a hinge  25  that allows movable portion  22  to freely move relative to portion  24 . It is envisioned that the portion of toothbrush  10  containing the head  20  could be adapted for replacement by inserting a new head into the powered portion of the toothbrush at or about the location indicated by reference numeral  28 . 
   The stationary  24  and movable  22  portions of the toothbrush head  20  contain cleaning elements  30 . Cleaning elements  30  are arranged in both portions of head  20  in a known manner. Any suitable form of cleaning elements may be used as the cleaning elements  30  in the broad practice of this invention. The term “cleaning elements” is intended to be used in a generic sense which could include conventional fiber bristles or massage elements or other forms of cleaning elements such as elastomeric fingers or walls arranged in a circular cross-sectional shape or any type of desired shape including straight portions or sinusoidal portions. Where bristles are used, the bristles could be mounted to tuft blocks or sections by extending through suitable openings in the tuft blocks so that the base of the bristles is mounted within or below the tuft block. 
   It is to be understood that the specific illustration of the cleaning elements is merely for exemplary purposes. The invention can be practiced with various combinations (such as stapled or in-mold technology bristles, etc.) and/or with the same bristle or cleaning element materials (such as nylon bristles, spiral bristles, rubber bristles, etc.) Similarly, while the Figures illustrate the cleaning elements to be generally perpendicular to head  20 , some or all of the cleaning elements may be angled at various angles with respect to the surface of head  20 . It is thereby possible to select the combination of cleaning element configurations, materials and orientations to achieve specific intended results to deliver additional oral health benefits, like enhanced cleaning, tooth polishing, tooth whitening and/or massaging of the gums. 
   The changes in orientation of movable portion  22  during operation are best understood by comparing  FIGS. 2 and 3 . Movable portion  22  has a flange  26  attached thereto extending from the area of movable portion  22  adjacent the last row of cleaning elements and extending lengthwise toward the drive shaft  18 . This flange  26  may be molded as part of movable portion  22  or affixed thereto. The flange  26  terminates at a tab  32  which is preferably aligned approximately perpendicular to the axis of drive shaft  18 . 
   Tab  32  at the end of flange  26  contains a slot  34  for receipt of an offset end  36  or elbow of drive shaft  18  (See  FIGS. 2 and 4 ). As drive shaft  18  rotates unidirectionally under motor power the offset end  36  of the shaft  18  engages the side edges of slot  34 . This causes the flange  26  to rotate counterclockwise around hinge  25  from a position immediately adjacent the back side  27  of the stationary portion  24  of head  20  ( FIG. 2 ) to a position 15–30 degrees (angle θ) from that position  6  ( FIG. 3 ). As the drive shaft rotates, typically at several hundred revolutions per minute, movable portion  22  of head  20  rapidly moves about hinge  25  resulting in a vigorous passage of cleaning elements  30  over the user&#39;s teeth and gums. This rapid movement helps to clean the user&#39;s teeth and stimulate the user&#39;s gums. 
     FIGS. 4 and 5  illustrate alternative configurations  34  and  34 A for slot  34 . Slot  34  of  FIG. 4  is closed at both ends to contain the offset end  36  of shaft  18  whereas slot  34 A shown in  FIG. 5  allows movement of offset end  36  across the entire width of tab  32  attached to flange  26 . 
   Flange  26  is preferably formed of a moderately flexible material that permits its movement independent of movable portion  22  of the toothbrush head  20 . Thus, if the user applies considerable force on the end of movable portion  22 , that tends to keep it in the position shown in  FIG. 4  while drive shaft  18  is turning, the flexibility of flange  26  will allow the motor to continue turning even though the movable portion  22  of head  20  is not moving or only slightly moving. This flexibility in flange  26 , coupled with the slot  34  or  34 A in tab  32 , prevents stalling of motor  12  in those situations where unusual pressure is exerted on the movable portion  22  of head  20 . 
   Under normal operation tab  32  will be displaced in a plane perpendicular to the axis of the toothbrush, and the drive shaft  18 , as the offset end  36  of that shaft rotates with the shaft. The amount of movement of tab  32 , and consequent movement of movable portion  22  can be regulated by the distance between the axis of drive shaft  18  and the offset end  36  of that shaft.  FIG. 4  illustrates this movement as the drive shaft  18  moves to opposite extremes of rotation. The full lines in  FIG. 4  represent the placement of tab  32  when movable portion  22  of head  20  is in the position shown in  FIG. 2 . The phantom lines correspond to its position when movable portion  22  is in the  FIG. 3  position. 
   To improve the cleansing of toothbrush  10  and preserve the operating parts  18 ,  26  and  32  from corrosion and or contamination, a cover  38  is placed over these parts. The cover  38  is preferably flexible or molded to allow free movement of flange  26  under power of drive shaft  18 .