Abstract:
There is provided a toothbrush head for an electric toothbrush, in accordance with an aspect of the present invention. A camshaft passes substantially through the main body of the toothbrush head and is adapted for connection to a motor to rotate the shaft. The camshaft has a first section that defines a longitudinal axis. A first bristle head is rotatably mounted to the main body for rotation between a first rotational position and a second rotational position. A second bristle head is slidably mounted to the main body proximate the tip and is moveable between a first position proximate to the longitudinal axis and a second position spaced from the longitudinal axis. The rotation of the camshaft drives the first bristle head between the first rotational position and the second rotational position and second bristle head from the first position to the second position.

Description:
CROSS-REFERENCE  
       [0001]    This application is based on, and claims priority from, U.S. Provisional Application Serial No. 60/433,509, filed Dec. 16, 2002. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to electric toothbrushes and particularly to an electric toothbrush that comprises an inline arrangement of a rotary oscillating bristle head, and a pulsating bristle head.  
         BACKGROUND  
         [0003]    The use of manual toothbrushes has, of course, been known for many years. Indeed, the use of mechanical toothbrushes, typically those that are electrically driven, has been known for a number of years. The purpose, in any event, is to clean the teeth, usually with a toothbrush that comprises a plurality of bristles that are used in conjunction with a dentifrice. Very often, the dentifrice is mildly abrasive.  
           [0004]    The dental profession has propounded, for many years, a technique known as the “Bass Technique” which, if properly performed, is said to achieve superior results in terms of cleaning one&#39;s teeth using a manual. toothbrush. Essentially, the Bass Technique requires the user to position a manual toothbrush over a zone of the teeth, and then to use very short strokes so as to more or less vibrate the brush at that zone where the brush has been located. This short-stroke brushing should continue for a period of time—typically, twenty strokes to forty strokes—so as to remove any foreign material from that zone. The brush is then repositioned and typically another twenty to forty short strokes are performed. Because each zone is very small, the Bass Technique can be very time consuming. Moreover, since it is a requirement that the strokes be very short which, in turn, requires excellent muscle control, exercising the Bass Technique can be very tiring.  
           [0005]    The theory is that, at the end of any given stroke, the bristles will flex so as to become oriented in such a manner that the ends of the bristles point generally away from the direction of the travel of the bristles across the teeth. However, at the beginning of the next stroke, in the opposite direction, the still-flexed bristles will then be pointed in the direction of the stroke and this may cause the bristle to chisel the foreign material away from the teeth for a moment before the bristle again begins to flex so as to sweep across the surface of the tooth in the zone where it is located.  
           [0006]    The Bass Technique has been applied to a variety of electric toothbrushes. U.S. Pat. No. 5,259,083, issued Nov. 9, 1993 to Stansbury, and reissued as RE35941, teaches a plurality of tuft blocks which are mounted in sliding relationship one with another, and which are driven by a camshaft so as to reciprocate inwardly and outwardly from the head of the toothbrush assembly. Toothbrushes in keeping with the teaching of this patent are sold in association with the BUTLER trademark. A similar cam driven structure is taught in U.S. Pat. No. 5,778,474, issued Jul. 14, 1998, to Shek.  
           [0007]    Another manner for brushing teeth comprises a variation of the Bass Technique, whereby oscillatory movement is imparted to a toothbrush. Of course, such oscillatory movement is not capable of being executed manually. Most electric toothbrushes provide groups of bristles in concentric circles, where the brush head thus provided is rotated or, more usually, it is reciprocally rotated.  
           [0008]    This oscillatory technique has been implemented in a variety of electric toothbrushes. For example, U.S. Pat. No. 5,120,225 issued to Amit teaches a mechanical toothbrush by which longitudinal reciprocation of the handle transfers oscillatory rotation to a rotatable bristle tufted head that is mounted between two longitudinally spaced clusters of fixed bristle tufts.  
           [0009]    U.S. Pat. No. 5,625,916 issued May 6, 1997 to McDougall, teaches an electric toothbrush having a circular bristle head that oscillates in a rotary manner, driven by a rotatable shaft which couples to a slot in one side of the bristle head and thereby functions as a cam. Toothbrushes in keeping with the teachings of this invention are sold in the market in association with a COLGATE trademark.  
           [0010]    Presently, purchasers of electric toothbrushes have been forced to choose between toothbrushes implementing the Bass technique or the oscillatory technique. Thus there is a need to have a single electric toothbrush that incorporates both techniques to achieve maximal cleaning.  
         SUMMARY  
         [0011]    There is provided a toothbrush head for an electric toothbrush, in accordance with an aspect of the present invention. The toothbrush head has a main body extending between a coupling interface and a tip. A camshaft passes substantially through the main body and is adapted for connection to a motor to rotate the shaft. The camshaft has a first section proximate the coupling interface which defines a longitudinal axis.  
           [0012]    A first bristle head is rotatably mounted to the main body proximate the tip. The first bristle head is mounted to rotate about a rotational axis between a first rotational position and a second rotational position. The first bristle head is provided with a plurality of bristles.  
           [0013]    A second bristle head is slidably mounted to the main body proximate the tip. The second bristle head is moveable between a first position proximate to the longitudinal axis and a second position spaced from the longitudinal axis. The second bristle head has a plurality of bristles.  
           [0014]    The first bristle head is drivable by rotation of the camshaft between the first rotational position and the second rotational position. The second bristle head is drivable by rotation of the camshaft from the first position to the second position.  
           [0015]    In another aspect of the present invention, the toothbrush head further has a plurality of bristles fixedly mounted to the main body.  
           [0016]    In an alternative aspect of the present invention, the first bristle head further includes a first cam follower adapted for abutment by the camshaft to rotate the first bristle head from the first rotational position to the second rotational position.  
           [0017]    In a further aspect of the present invention, the first bristle head further comprises a second cam follower adapted for abutment by the camshaft to rotate the first bristle head from the second rotational position to the first rotational position.  
           [0018]    In yet another aspect of the present invention, the rotation of the first bristle head from the first rotational position to the second rotational position is in a first rotational direction. The rotation of the first bristle head from the second rotational position to the first rotational position is in a second rotational direction. The second rotational direction is opposed to the first directional rotation.  
           [0019]    In yet a further aspect of the present invention, the camshaft is adapted such that the abutment of the first cam follower occurs 180 degrees out of phase with the abutment of the second cam follower over a full rotation of the camshaft.  
           [0020]    In still another aspect, the camshaft is adapted to abut the first and second cam followers such that the first bristle head undergoes reciprocal rotation between the first and second rotational positions while the camshaft is fully rotated.  
           [0021]    In a still further aspect, the second bristle head further includes a base portion. The base portion has a slot adapted to receive a pulsating portion of the camshaft. The pulsating portion of the camshaft is non-collinear with the longitudinal axis. The slot is adapted to transmit movement in a lateral direction to the second bristle head where the lateral direction is generally parallel to the bristle and perpendicular to the longitudinal axis.  
           [0022]    In another aspect, the first bristle head further includes a base portion. The base portion has a slot adapted to receive an oscillating portion of the camshaft. The oscillating portion of the camshaft is non-collinear with the longitudinal axis. The slot is adapted to transmit rotational motion to the first bristle head about a central axis of the first bristle head.  
           [0023]    In another embodiment of the present invention, there is provided an electric toothbrush having a toothbrush head with the features described above. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    The novel features which are believed to be characteristic of the present invention, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following drawings in which presently preferred embodiment(s) of the invention will now be illustrated by way of example. It is expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. Embodiments of this invention will now be described by way of example in association with the accompanying drawings in which:  
         [0025]    [0025]FIG. 1 is a plan view of a first embodiment of a toothbrush in accordance with the present invention;  
         [0026]    [0026]FIG. 2 is a partial sectional view of the toothbrush of FIG. 1 taken along line A-A;  
         [0027]    [0027]FIG. 3 is a perspective view of the toothbrush head of FIG. 1;  
         [0028]    [0028]FIG. 4 is a plan view of the toothbrush head of FIG. 3;  
         [0029]    [0029]FIG. 5 is a side elevation of the toothbrush head of FIG. 3;  
         [0030]    [0030]FIG. 6 is a sectional view taken along line B-B in FIG. 4, with the internal drive shaft in a first position;  
         [0031]    [0031]FIG. 7 is a sectional view taken along line C-C in FIG. 5 with the internal drive shaft in the first position;  
         [0032]    [0032]FIG. 8 is similar to FIG. 6, but with the drive shaft rotated 180°;  
         [0033]    [0033]FIG. 9 is similar to FIG. 7, but with the drive shaft rotated 180°;  
         [0034]    [0034]FIG. 10 is a perspective view of a pulsating bristle head of the toothbrush head of FIG. 1;  
         [0035]    [0035]FIG. 11 is a plan view of a second embodiment of a toothbrush in accordance with the present invention;  
         [0036]    [0036]FIG. 12 is a partial sectional view of the toothbrush of FIG. 11 taken along line D-D;  
         [0037]    [0037]FIG. 13 is a perspective view of the toothbrush head of FIG. 11;  
         [0038]    [0038]FIG. 14 is a plan view of the toothbrush head of FIG. 13;  
         [0039]    [0039]FIG. 15 is a side elevation of the toothbrush head of FIG. 13;  
         [0040]    [0040]FIG. 16 is a perspective view of a third embodiment of a toothbrush head in accordance with the present invention;  
         [0041]    [0041]FIG. 17 is a plan view of the toothbrush head of FIG. 16;  
         [0042]    [0042]FIG. 18 is a side elevation of the toothbrush head of FIG. 16;  
         [0043]    [0043]FIG. 19 is a sectional view taken along line G-G in FIG. 17, with the internal drive shaft in a first position;  
         [0044]    [0044]FIG. 20 is a sectional view taken along line H-H in FIG. 18 with the internal drive shaft in the first position;  
         [0045]    [0045]FIG. 21 is similar to FIG. 19, but with the drive shaft rotated 180°;  
         [0046]    [0046]FIG. 22 is similar to FIG. 20, but with the drive shaft rotated 180°; and  
         [0047]    [0047]FIG. 23 is a perspective view of the drive shaft arrangement of the third embodiment. 
     
    
     DETAILED DESCRIPTION  
       [0048]    The novel features which are believed to be characteristic of the present invention, as to its structure, organization, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following discussion in combination with the accompanying drawings.  
         [0049]    FIGS.  1  to  9  show a first embodiment of a toothbrush  10  in accordance with the present invention. Toothbrush  10  is composed of a power handle or handle section  12  coupled to a toothbrush head  14 . Handle section  12  is a generally cylindrical body extending from a base  16  to coupling interface  18 . As shown in FIG. 1, the diameter of the body of handle section  12  decreases towards the coupling interface  18 . Handle section  12  will generally house a motor  13  to drive a camshaft or central shaft  20  and a battery to power the motor. In addition, base portion  12  will often incorporate an activator  22  to start and stop the motor.  
         [0050]    Toothbrush head  14  is a generally cylindrical main body extending between a coupling interface  24  and a tip  26 . Tufts of bristles  28  extend outwardly near tip  26 , as seen in FIG. 2, in a single direction.  
         [0051]    Toothbrush head  14  and handle section  12  may be coupled together using a variety of configurations known in the art. The important feature of this coupling is that the drive shaft or central shaft  20 , which extends through toothbrush head  14 , is rotatably driven by a motor in handle section  12 . While toothbrush head  14  is shown and described as being detachable from handle section  12 , toothbrush head  14  and handle section  12  may be incorporated into a single unit.  
         [0052]    As shown in FIG. 3, bristles  28  are composed of two sets of tufts of bristles: reciprocating bristles  30  and pulsating bristles  32 . Reciprocating bristles  30  are mounted in separate tufts on a first bristle head or circular bristle block  34 . Circular bristle block  34  is rotatably mounted to the tip  26  of toothbrush head  14 . Pulsating bristles  32  are mounted to a second bristle head or pulsating bristle block  36 . Pulsating bristle block  36  is mounted next to circular bristle block  34  for motion perpendicular to the longitudinal axis of toothbrush head  14 .  
         [0053]    As shown in FIGS. 6 through 9, central shaft  20  is composed of five sections. For the purposes of describing the positioning of the various sections, reference will first be made to FIG. 6. Central shaft  20  begins with a first or main section  40  which extends from coupling interface  24  through most of toothbrush head  14 . Main section  40  defines a longitudinal axis and lies in a generally horizontal plane passing through toothbrush head  14  as shown in FIG. 6. Central shaft  20  continues to a pulsating section  42  positioned below pulsating block  36 . Pulsating section  42  lies parallel to and below the horizontal plane in which main section  40  is positioned. Central shaft  20  continues to a first oscillating section  44  which lies parallel to and above the horizontal plane in which main section  40  is positioned. A spindle section  46  of central shaft  20  is adjacent to first oscillating section  44  and lies within the horizontal plane. Finally, central shaft  20  terminates in a second oscillating section  48  which lies parallel to and below the horizontal plane. Preferably, the distance between second oscillating section  48  and the horizontal plane is equal to the distance between first oscillating section  44  and the horizontal plane.  
         [0054]    The sections of central shaft  20  will now be described with reference to FIG. 7. Main section  40  is at an angle from a vertical plane that bisects toothbrush head  14 . (In FIG. 7, this vertical plane would rise out of the page.) Pulsating section  42  is above the axis defined by main section  40 , as is second oscillating section  48 . First oscillating section  44  lies below the axis defined by main section  40 . Spindle section  46  is generally aligned with main section  40 .  
         [0055]    Spindle section  46  is mounted within a spindle bearing  50  below circular bristle block  34 . As the motor rotates the shaft, spindle section  46  remains in position with respect to toothbrush head  14 . The other sections, however, will rotate about the axis defined by main section  40 . FIGS. 8 and 9 show the toothbrush head with central shaft  20  rotated by 180° with respect to the position shown in FIGS. 6 and 7.  
         [0056]    The actions of each bristle block will now be described in more detail. Circular bristle block  34  is rotatable about a rotation axis at pin  52  which connects circular bristle block  34  to the main body of toothbrush head  14 . Central shaft  20  lies at an angle to the bisecting vertical plane of toothbrush head  14  so that pin  52  does not interfere with spindle section  46 . First and second oscillating sections  44  and  48  act as cams on a cam follower  54  projecting below the base of circular bristle block  34 . As central shaft  20  rotates, first and second oscillating sections  44  and  48  move in opposite directions (as viewed in FIGS. 7 and 9) away from the axis defined by main section  40 . The movement of first oscillating sections  44  against cam follower  54  causes circular bristle block  34  to rotate about pin  52  from the first rotational position shown in FIG. 7 to a second rotational position shown in FIG. 9 in a counter-clockwise direction (with reference to FIGS. 7 and 9). After first oscillating section  44  is not longer in contact with cam follower  54 , second oscillating section  48  abuts cam follower  54  to rotate circular bristle block  34  from the position shown in FIG. 9 back to that in FIG. 7 in a clockwise direction (with reference to FIGS. 7 and 9). The angle through which bristle head  34  rotates is determined by the distance between the longitudinal axis defined by the central shaft and the first and second oscillating sections  44  and  48  as well as the shape and size of cam follower  54 . Cam follower  54  as shown in FIGS. 7 and 9 is actually composed of a pair of cam followers, one of which is abutted by first oscillating section  44  and the other of which is abutted by second oscillating section  48 . Preferably, first and second oscillating sections  44  and  48  are equidistant from the longitudinal axis. In addition, in the embodiment shown, first and second oscillating sections  44  and  48  are 180° out of phase, first and second oscillating section may be out of phase at lesser or greater intervals than 180°.  
         [0057]    Pulsating bristle block  36  has a cam follower  60  projecting downwardly therefrom, as shown in FIG. 10. Pulsating section  42  of central shaft  20  passes through an opening  62  having an obround cross-section. Pulsating bristle block  36  is maintained within toothbrush head  14  in this manner and is not otherwise affixed to the casing of toothbrush head  14 . (A cavity within toothbrush head accommodates the sliding motion in the vertical direction.) As central shaft  20  is rotated by the motor, pulsating section  42  of the central shaft moves vertically from a first position as shown in FIG. 6 to a second position shown in FIG. 8. The obround cross-section of opening  62  has a major axis in the horizontal direction and a minor axis in the vertical direction. The minor axis is only slightly larger that the diameter of central shaft  20 . As a result, when pulsating section  42  will rise and fall as pulsating section  42  moves upwardly and downwardly with respect to the longitudinal axis. The major axis is sized such that little or no lateral motion is imparted to pulsating bristle block  36  as pulsating section moves vaertically with respect to central shaft  20 . In addition, cam follower  62  is positioned away from the central vertical axis of pulsating bristle block  36  so as to accommodate the angled positioning of central shaft  20 .  
         [0058]    Thus, as central shaft  20  is rotated, pulsating bristle block  36  is moved into and out of the teeth while circular bristle block  34  is rotated about pin  52  in a reciprocating manner. As the bristles are passed over teeth during cleaning, two advantageous methods of cleaning are simultaneously applied.  
         [0059]    [0059]FIGS. 11 through 15 show an alternative embodiment of toothbrush head  14 . The only difference with the first embodiment is that toothbrush head  14  has a third stationary set of bristles  70  generally surrounding pulsating bristles  30 . The third set of bristles will perform a third form of cleaning as the toothbrush is moved in a longitudinal direction by the user.  
         [0060]    [0060]FIGS. 16 through 23 show a third embodiment of toothbrush head  14 . In this embodiment, central shaft  120  is composed of three sections. The first is a main section  140  which extends from coupling interface  24  through much of toothbrush handle  14 . Main section  140  defines a longitudinal axis. Central shaft  120  continues to pulsating section  142  which lies parallel to the longitudinal axis, but is spaced therefrom. Central shaft  120  terminates in an oscillating section  144 . Oscillating section  144 , as shown in FIG. 19, is not parallel to the longitudinal axis. It begins at a point further from the longitudinal axis than pulsating section  142  and is then angled inwardly towards the longitudinal axis.  
         [0061]    A spindle projection  146  extends downwardly from a portion of the toothbrush head to act as a bearing for the tipwards end of main section  140 .  
         [0062]    Circular bristle block  34  is oscillated in a reciprocating manner using a somewhat different manner than in the first embodiment. Circular bristle block  34  has a cam follower  150  located near the periphery of the bristle block furthest from the tip of toothbrush head  14 . Cam follower  150  is composed of at least two downwardly projecting walls having a slot therebetween in which oscillating section  144  is placed. Oscillating section  144  is angled such that it is aligned with pin  52  of circular bristle block  34  throughout the complete revolution of central shaft  120 . The rotation of central shaft  120  causes oscillating section  144  to act as a cam and push against double-sided cam follower  150 . The rotation of central shaft  20  imparts rotational movement to the first bristle block. This results in the reciprocating rotation of circular bristle block  34  about pin  52 .  
         [0063]    Pulsating bristle block  36  is moved by pulsating section  142  in the same manner as described in the first embodiment. However, in this case, cam follower  60  is now centrally located on the base of pulsating bristle block  36  as the main section lies in a central longitudinal axis.  
         [0064]    [0064]FIGS. 19 and 20 show toothbrush head  14  with the central shaft  120  in a first position. Pulsating bristle block  36  is in a raised position and circular bristle block  34  is angled to a first position. In FIGS. 21 and 22, central shaft  120  is rotated by 180°. Pulsating block  36  is in a lower position and circular bristle block  34  is angled to a second position.  
         [0065]    While not explicitly shown in this embodiment, it would be obvious to those skilled in the art to add a set of stationary bristles to toothbrush head  14  to augment the cleaning process.  
         [0066]    The embodiments shown describe a detachable toothbrush head. However, the mechanisms described above could be incorporated into a unitary toothbrush design where the toothbrush head is not detachable or replaceable. In such a case, the central shaft may be affixed to the motor directly rather than through a coupling.  
         [0067]    In addition, a variety of different configurations of the bristle blocks may be designed. For example, the pulsating block may be located closer to the tip than the circular blocks. In another embodiment, multiple pulsating blocks may be included with alternating pulsing action or may be synchronized. A pair of bristle blocks may be mounted on either side of the circular bristle block.  
         [0068]    Each of the bristle blocks in the described embodiments are moved between their first and second positions by a dual cam action. Alternatively, a single cam action could be used to move the bristle blocks from a first position to a second position. A biasing means, such as a spring, could be used to return the bristle block from the second position to the first position. In a further alternative, the cam follower of the pulsating bristle block could be adapted such that the camshaft only acts to move the pulsating bristle block from the first position to the second position. The pressure from the user pressing the bristles against the user&#39;s teeth will cause the pulsating bristle block to return to the first position.  
         [0069]    Central shaft  20  and  120  as shown is a camshaft having a constant diameter, with sections bent such that they are no longer collinear with main sections  40  and  140 . It will be obvious to those skilled in the art that traditional cam discs could be mounted on a single straight camshaft to achieve the same movement of the bristle blocks.  
         [0070]    In another variation on the present invention, the circular bristle block and cams on the central shaft may be adapted for continuous rotation in a single direction. One method of incorporating this motion could be to have a bevel gear mounted to the central shaft with a corresponding bevel gear mounted at a right angle to the base of the circular bristle block.  
         [0071]    In another variation on the present embodiments, the motor may be adapted to only partially rotate central shaft  20  in one direction followed by a partial rotation in a second direction opposite to the first direction. The organization of cams and cam followers would be adjusted accordingly to effect the same motions described above.  
         [0072]    Other variations of the above principles will be apparent to those who are knowledgeable in the field of the invention, and such variations are considered to be within the scope of the present invention. Other modifications and/or alterations may be used in the design and/or manufacture of the apparatus of the present invention, without departing from the spirit and scope of the accompanying claims.  
         [0073]    Throughout this specification and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not to the exclusion of any other integer or step or group of integers or steps.  
         [0074]    Moreover, the word “substantially” when used with an adjective or adverb is intended to enhance the scope of the particular characteristic; e.g., substantially perpendicular is intended to mean perpendicular, nearly perpendicular and/or exhibiting characteristics associated with perpendicularity.