Abstract:
An electric toothbrush in which the brushing head moves in an elliptical motion such that, on the brushing stroke, the bristles are proximate the teeth, and in the recovery portion of the cycle the bristles are pulled away from the teeth. A position sensitive switch automatically switches from a forward to a reverse operation of the electric motor, depending on the positioning of the toothbrush in a user&#39;s hand, allowing the user to brush both the upper and lower teeth using a stroke carrying the bristles from the gum line to the ends of the teeth, as is recommended by dental professionals, without having to move the toothbrush from hand to hand or manually move the switch from the forward to the reverse positions. A bridge pad engages the face of the teeth, maintaining a proper distance between the teeth and bristles during the elliptical rotation of the brush head.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to electric toothbrushes. More particularly, the invention comprises an electric toothbrush having a reversible, elliptical rotation pattern of the brushing head, allowing strokes which brush away from the gums, regardless of which hand the user uses or whether he is brushing the upper or lower teeth.  
         [0003]     2. Description of the Prior Art  
         [0004]     Electric toothbrushes are well known in the art. Most electric toothbrushes, however, provide only an up and down motion, thereby brushing into the gum on half of the brush strokes. Most of the brushes which do provide a rotary motion, and thus only brush away from the gum, as advised by dental professionals, present other problems.  
         [0005]     U.S. Pat. No. 5,974,296, issued to Tit Shing Wong on Aug. 18, 1998, discloses an ELECTRIC TOOTHBRUSH, having a reversible, rotary brush head activated by a switch at the brush head, which is placed inside the mouth. By contrast, the switch of the present invention is contained within the handle of the toothbrush and is activated by the position of the toothbrush in the user&#39;s hand, and the brushing action of the brush head is performed with a stroking motion as opposed to a rotary motion. The present invention further includes a spacer to maintain the brush at a proper distance from the teeth during the brushing and recovery strokes, not found in Wong&#39;s brush.  
         [0006]     Celso Caroli discloses an ELECTRICALLY DRIVEN CONTINUOUS TOOTH BRUSH in U.S. Pat. No. 4,275,479, issued on Jun. 30, 1981. A reversible, rotating brush head is controlled by a manual switch controlled by the user&#39;s fingers. By contrast, the switch of the present invention is contained within the handle of the toothbrush and is activated by the position of the toothbrush in the user&#39;s hand, and the brushing action of the brush head is performed with a stroking motion as opposed to a rotary motion. The present invention further includes a spacer to maintain the brush at a proper distance from the teeth during the brushing and recovery strokes, not found in Caroll&#39;s brush.  
         [0007]     A METHOD AND APPARATUS FOR CONVERTING A POWER-DRIVEN TOOTHBRUSH INTO A POWER-DRIVEN FLOSSING DEVICE is disclosed in U.S. Pat. No. 6,047,711, issued to Daniel A. Wagner on Apr. 11, 2000. The toothbrush and flosser, as described do not provide elliptical rotation of the head or means of spacing the brushes away from the teeth.  
         [0008]     None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.  
       SUMMARY OF THE INVENTION  
       [0009]     The present invention provides an electric toothbrush which has a reversible, elliptical brushing motion which allows a user to brush from the gums to the tips of the teeth, regardless of which hand he is using or whether he is brushing the upper or lower teeth. The brush bristles are split such that they extend on either side of a soft spacer pad which may be rested against the teeth. The spacer maintains the bristles at a given distance away from the teeth, such that they brush against the teeth on the near, brushing stroke, portion of an elliptical orbit about an axis of the shaft while pulling away from the teeth on the far, recovery, portion of the elliptical orbit. An automatic, position sensitive switch allows the brush shaft to change the direction of its elliptical rotation about its axis, allowing a user to switch the brushing direction of the bristles by a simple change of the angle of the wrist in order to change from brushing the left or right or the front or the back of the teeth. A three position switch on the handle allows the user to selectively reverse the motor for brushing the upper teeth or the lower teeth.  
         [0010]     Accordingly, it is a principal object of the invention to provide an electric toothbrush which is capable of brushing both the upper and lower teeth, with the bristles stroking away from the gums, as is recommended by dental professionals.  
         [0011]     It is another object of the invention to provide an electric toothbrush which is able to change the direction of the bristle stroke by a simple change of wrist position.  
         [0012]     It is a further object of the invention to provide an electric toothbrush having an spacer element to maintain the brush shaft away from the teeth, allowing the bristles to brush the teeth on the brushing portion of the cycle while preventing the shaft from hitting the teeth as it rotates about its axis.  
         [0013]     Still another object of the invention is to provide an electric toothbrush which may, optionally, be either AC or DC operated.  
         [0014]     An additional object of the invention is to provide an electric toothbrush which is relatively light weight, yet durable.  
         [0015]     It is again an object of the invention to provide an electric toothbrush which is relatively economical to purchase and operate.  
         [0016]     It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.  
         [0017]     These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     Various other objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein:  
         [0019]      FIG. 1  is a perspective view of the toothbrush of the present invention.  
         [0020]      FIG. 2  is a side view of the toothbrush of the present invention.  
         [0021]      FIG. 3  is a cross sectional view of the toothbrush of the present invention as shown at line  3 - 3  of  FIGS. 1 and 2 .  
         [0022]      FIG. 4  is a cross sectional view of the toothbrush of the present invention as shown at line  4 - 4  of  FIG. 1 .  
         [0023]      FIG. 5  is a detailed view of the electric motor, electronic control board and direction control mechanism, as isolated at  5  of  FIG. 4 .  
         [0024]      FIG. 6  is a detailed cross sectional view of the electric motor assembly of the toothbrush at line  6 - 6  of  FIG. 4 .  
         [0025]      FIG. 7  is a detailed cross sectional view of the joint and elliptical rotation mechanism at line  4 - 4  of  FIG. 1  as isolated at  7  of  FIG. 4 .  
         [0026]      FIG. 8  is a detailed cross sectional view of the joint of the elliptical rotation mechanism at line  3 - 3  of  FIG. 1 .  
         [0027]      FIG. 9  is a cross sectional view of the elliptical rotation mechanism at line  9 - 9  of  FIG. 4 .  
         [0028]      FIG. 10  is a cross sectional view of the elliptical rotation mechanism at line  10 - 10  of  FIG. 4 .  
         [0029]      FIG. 11  is a view of the brush head of the tooth brush of the present invention brushing a lower tooth with the bristles at the brushing stroke position of the brush drive shaft&#39;s elliptical cycle.  
         [0030]      FIG. 12  is a view of the brush head of the tooth brush of the present invention and a lower tooth with the bristles at the recovery portion of the brush drive shaft&#39;s elliptical cycle.  
         [0031]      FIG. 13  is a partially cut away perspective view of the toothbrush showing the operating systems with additional detail.  
         [0032]      FIG. 14  an exploded perspective view of the toothbrush showing the interlinking of the operating mechanisms between the various segments of the assembly.  
         [0033]      FIG. 15  is a cut away view of an alternative embodiment of the toothbrush having an alternative elliptical rotation mechanism.  
         [0034]      FIG. 16  is a cross sectional view of the alternative elliptical rotation mechanism at line  16 - 16  of  FIG. 15 .  
         [0035]      FIG. 17  is a cross sectional view of the alternataive elliptical rotation mechanism at line  17 - 17  of  FIG. 15 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0036]     The toothbrush  1 , generally presented at  FIGS. 1 and 2 , includes a handle  100  and a brush head  140 . Handle  100  is further composed of a body housing  112  and shoulder housing  124 , while brush head  140  is further composed of brush shaft  142  and bristles  144 . A switch  212  controlling the a motor  200  ( FIG. 5 ) located within the body housing  112  is located on the body housing  112 . The body housing  112  is substantially cylindrical in shape, having a closed lower end and an open upper end. It would be evident to one of ordinary skill in the art, however, that the body housing  112  may take any one of a variety of other shapes without departing from the spirit of the invention. The shoulder housing  124  is substantially frustoconical in shape having a larger, open lower end adapted to mate with the open upper end of the body housing  112  and a substantially closed upper end with an aperture centered therein allowing the passage of a brush drive shaft (to be detailed herein below).  
         [0037]     Still referring to  FIGS. 1 through 4 , a brush spacer unit  150  extends upwardly from the top of the shoulder housing  124 . The brush spacer unit  150  consists of a substantially cylindrical brush spacer base  152 , which extends from the top of the shoulder housing  124 , and a pair of brush spacer extenders  154 , extending from the top of the brush spacer base  152 , one on each side of the brush shaft  142 . At a distal end, the brush spacer extenders  154  are joined by a brush spacer bridge  156 , which passes in front of the brush shaft  142 , through a gap in the bristles  144 . The brush spacer bridge  156  is faced by a brush spacer pad  158 .  
         [0038]      FIGS. 3 and 4  are front and side cross sectional views, respectively, showing the motor assembly  200  and elliptical rotation mechanism  300  as they are mounted within the body housing  112  and shoulder housing  124 , the details of which will be discussed hereinbelow.  
         [0039]     Turning now to  FIGS. 5 and 6 , the motor assembly  200  contains a reversible electric motor  210  which is powered by an electrical energy source (not shown) which could be either an AC power cord attached to a power grid, or a DC battery contained within the body housing  112 . In the interest of safety and convenience, a DC battery (not shown) is the preferred power source, whether replaceable or rechargeable. The electric motor  210  is controlled by a three position switch  212  which passes through the wall of the body housing  112 . The three positions of the switch  212  consist of “off”, and a pair of reversing positions, which are selectively used for brushing the upper or the lower teeth. The electric motor  210  is further controlled by a directional controller  214  which allows the electric motor  210  to automatically reverse its direction of rotation. The directional control  214  consists of an electronic control board  216  and a pendulum  218  suspended from a pivot point  220  within a slot  222  in the electric control board  216 . A pair of infra-red (IR) transceivers  224  and  226  are situated to the right and left, respectively, of the pendulum  218 , such that the two elements of each transceiver  224  and  226  are on opposite sides of the slot  222 . As the user of the toothbrush  1  changes the angle of the brush in his hand, pendulum  218  swings between the two elements of either transceiver  224  or  226 , interrupting the infra-red beam. The interruption of the IR beam causes electronic control board  216  to reverse the direction of rotation of motor drive shaft  228  and drive gear  230 , thus reversing the direction of rotation of the brush head  140 . After the three position switch  212  is set for either the upper or lower teeth, the directional controller  214  reverses the direction of the electric motor  210  as the angle of the toothbrush  1  changes shifting from the right to left teeth, or front and back of the teeth. It would be evident to one of ordinary skill in the art that a variety of different position sensitive switching mechanisms known in the art, such as, but not limited to, a mercury switch, could be used in lieu of pendulum  218  and IR transceivers  224  and  226 , without departing from the spirit of the present invention.  
         [0040]     At  FIGS. 7, 8 ,  9  and  10  the elliptical drive mechanism  300 , which converts the rotary motion of the motor drive shaft  228  to an elliptical motion of the brush head  140 , is illustrated. The elliptical drive mechanism  300  has a body block  310  which engages the interior of the lower end of the shoulder housing  124  such that drive gear  230  at the end of motor drive shaft  228  engages lower gear  312 , which is fixedly attached, concentrically, to the lower end of gear shaft  314 , which passes upwardly through body block  310 . Upper gear  316  is fixedly attached, concentrically, to the upper end of gear shaft  314 . A metal pin  318 , having a ball head at its upper end, is fixedly attached, eccentrically and normal to the upper surface of upper gear  316 . Upper gear  316  engages gear  320 , which is rotatably and concentrically attached to a gear shaft  322 , fixedly embedded in body block  310 . A second metal pin  324 , also having a ball head, is fixedly attached, eccentrically and normal to the upper surface of gear  320 . The ball head of each of pin  318  and  324  are movably fitted into a cylindrical opening in the bottom of a cube-shaped drive cap  326 ,  328 , respectively.  
         [0041]     Still referring to  FIGS. 7 and 9 , an elliptical drive head  330  is of a diameter sufficiently smaller than the interior diameter of shoulder housing  124  ( FIG. 2 ) to allow free movement within shoulder housing  124 . Within the lower surface of elliptical drive head  330  are a groove  332  and a groove  334 , adapted to movably receive drive caps  326  and  328 , respectively.  
         [0042]     Groove  332  is located in the lower surface of elliptical drive head  330  near its circumference. It is normal to and centered on a diameter line of elliptical drive head  330 . Groove  334 , also on the lower surface of elliptical drive head  330 , lies along the aforementioned diameter line bisecting, but not joining groove  332  and is disposed such that a first end is proximate groove  332  and a second end is proximate the circumference of elliptical drive head  330 . The second end of groove  334  is approximately equidistant from the circumference of elliptical drive head  330  as is the outer edge of groove  332 . Within the upper surface of elliptical drive head  330  is a cylindrical drive shaft receptacle  336 , adapted to frictionally receive the lower end of brush drive shaft  338 .  
         [0043]     Drive caps  326 ,  328  each fit into the grooves  332  and  334 , respectively, such that as the gears  316  and  320  turn, thereby moving the drive caps  326 ,  328  within the grooves  332  and  334 , elliptical drive head  330  moves eccentrically within the shoulder housing  124 , thereby causing the lower end of the brush drive shaft  338  to move eccentrically. The eccentric motion of the lower end of the brush drive shaft  338  is transferred to the upper end and thus the bristles,  144  by the pivot assembly  340 , further detailed hereinbelow.  
         [0044]     Brush drive shaft  338  is substantially a parallelepiped having a length substantially greater than its substantially square cross section. A rounded protrusion  339  may be located in two of the opposite faces of the length of brush drive shaft  338  proximate its center point provide additional space for a round pivot pin  344  and pivot pin aperture  344 A which penetrates brush drive shaft  338  proximate its midpoint, passing between the flat faces of brush drive shaft  338 .  
         [0045]     Referring now to  FIGS. 7 and 8 , there is shown a pivot assembly  340  which occupies a void within shoulder housing  124 . The pivot assembly  340  is composed of a substantially solid and rectilinear bar dimensioned so that its ends frictionally engage the interior walls of shoulder housing  124 . A pivot aperture  342  within pivot assembly  340  allows brush drive shaft  338  to pass vertically therethrough. A pivot pin  344  passing through pivot pin aperture  344 A of brush drive shaft  338  is anchored at each of its two ends into the interior walls of pivot assembly  340 , movably securing brush drive shaft  338  within pivot assembly  340 .  
         [0046]     It would be evident to one of ordinary skill in the art that various bushings and bearings would be required to facilitate the smooth working of gears and pivot points. These bushing and bearings are well known in the art, therefore they will not be discussed in further detail herein. It would, likewise, be evident to one of ordinary skill in the art that toothbrush  1  could be manufactured of a variety of different materials, but for the sake of economy, various polymerics or plastics would be preferable for housings, shafts and gears, although light metals could also be utilized.  
         [0047]     In operation, switch  212  activates electric motor  210  in one of either a clockwise or counter-clockwise direction, the direction depending on the initial position of pendulum  218 . The user, by rotating his wrist, and thereby toothbrush  1 , causes pendulum  218  of directional control  214  to swing in a direction corresponding to the rotation of the wrist. As pendulum  218  breaks the IR beam of either IR transceiver  224  or  226 , directional controller  216  is caused to reverse the direction of motor drive shaft  228  of motor  210 . Drive gear  230 , mounted at the end of motor drive shaft  228 , being rotatably engaged with lower gear  312  causes lower gear  312  to drive gear shaft  314 , and thus, upper gear  316 . Upper gear  316 , in turn, drives gear  320 , respectively causing elliptical drive head  338  to move elliptically. It will be noted that neither elliptical drive head  330  nor brush drive shaft  338  rotate, but rather, keep a constant orientation in a single direction. Brush drive shaft  338 , pivoting about pivot pin  344 , transfers the elliptical motion to brush shaft  142  of brush head  14 , and thus to the bristles  144  of brush head  14 . Again, by twisting the wrist, the user may reverse the direction of elliptical rotation of brush head  14  so that the bristles  114  may travel downwardly for brushing the upper teeth or upwardly for brushing the lower teeth, as is typically recommended by most dental professionals.  
         [0048]     Referring now to  FIGS. 15, 16  and  17 , an alternate embodiment of an elliptical drive mechanism  400  is presented. Instead of being gear driven, the elliptical drive mechanism is driven directly by electric motor  210 . In the alternate embodiment  400 , a motor drive shaft  228  terminates in the lower surface of a round drive plate  410 , which has a groove  412  disposed in its upper surface. Brush drive shaft  414  has an elongate rectilinear form having a ball capped pin  416  at its lower end, the ball of which is movably secured in a cubic drive cap  418 . A spring  420  moveably holds the cubic drive cap  418  eccentrically in position within the groove  412 . The rotary motion of motor drive shaft  228  and drive plate  410  is converted to an elliptical motion of brush drive shaft  414  by the movable relationship of pin  416  and drive cap  418 , as well as the movable relationship of drive cap  418  within groove  412 . A round guide plate  442  is adapted to fit frictionally within the inner walls of shoulder housing  124 . Guide plate  442  has an elliptical aperture  424  at its center, which houses a roller bearing assembly  426 , which in turn surrounds an end of brush drive shaft  414 . Pivot assembly  340  of the preferred embodiment remains, unchanged, in the alternate embodiment. The combined actions of the eccentricity of the end of brush drive shaft  414  in drive plate  410 , the elliptical aperture in guide plate  442  and the fixed pivot point of pivot assembly  340  provide the elliptical motion to brush head  14 .  
         [0049]     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.