Abstract:
A toothbrush head of an electric toothbrush, the toothbrush extending longitudinally and having a hand part, the toothbrush head including a drive rocker, a brush-head carrier coupled to the drive rocker, a main bristle carrier and an additional bristle carrier, both carriers bearing a bristle arrangement and moveably attached to the brush-head carrier and driven in oscillation by the drive rocker, and a drive-coupler affixed to at least one of the bristle carriers and coupled to the drive rocker. The head can include two separately mounted bristle carriers, supporting bristle arrangements, which are driven about different movement axes by the drive rocker to enhance the cleaning action of the toothbrush.

Description:
TECHNICAL FIELD 
   This description relates to a toothbrush head of an electric toothbrush which has a hand part with a drive, with a brush-head carrier, which can be connected to the hand part, and with a plurality of bristle carriers which each bear a bristle arrangement, are mounted in a moveable manner on the brush-head carrier and can be driven in oscillation by the drive, it being possible for the bristle carriers to be coupled to a drive transmitter by means of a drive coupling in each case. 
   BACKGROUND 
   U.S. Pat. No. 5,524,312 discloses an electric toothbrush, on the brush head of which are provided two separate bristle carriers which are driven by a common drive shaft. One bristle carrier executes an oscillating rotary movement about an axis which is perpendicular to the brush handle. The other bristle carrier is pivoted back and forth about an axis which is parallel to the brush handle. Although this bristle-carrier arrangement causes an active relative movement between the clusters of bristles, it is disadvantageous insofar as it is restricted to a specific drive mechanism, namely a transmission rod which reciprocates in the axial direction. The additional bristle carrier, which is arranged further rearwards in the direction of the hand part, requires a cylindrical underside with a special curved groove, in which an engagement protrusion of the longitudinally oscillating drive axis engages. In addition, the configuration of the clusters of bristles arranged on the two bristle carriers is not particularly suited for cleaning spaces between the teeth effectively. 
   SUMMARY 
   According to one aspect, a toothbrush head and a corresponding toothbrush provide straightforward, effective drive of the two bristle carriers. 
   The bristle carriers thus each have drive-coupling means by means of which they can be coupled to a common drive rocker of the drive, it being possible for said rocker to be rocked transversely to the longitudinal direction of the toothbrush. A better cleaning action can easily be achieved by the provision of two separately mounted bristle carriers, which are driven about different movement axes by a common drive rocker. The relative movement of the bristle arrangements mounted on the bristle carriers assists the cleaning movement, with the result that the cleaning action is not just produced by the person cleaning their teeth. 
   The drive rocker for driving the bristle carriers may be designed in different ways. According to one configuration of the invention, the bristle carriers may be coupled to a drive rocker which can be rocked in relation to a plurality of axes, describes a double-cone-shaped circulatory path and is assigned to the hand part of the toothbrush. As an alternative, it is also possible to provide a drive rocker which can be rocked in relation to just one axis and of which the rocking axis extends essentially perpendicularly to the longitudinal direction of the toothbrush, preferably such that the drive rocker can be rocked in a plane which contains the longitudinal axis of the toothbrush and is oriented perpendicularly to the main bristle direction defined by the clusters of bristles, i.e. is located essentially parallel to the planes defined by the bristle carriers. As an alternative, it is also possible for the drive rocker to rock in a plane which contains the main bristle direction and the longitudinal axis of the toothbrush, in particular when the bristle arrangements are to be driven with a picking movement. It is preferable, however, to provide the above described drive rocker which can be rocked in relation to a plurality of axes and describes a double-cone-shaped drive movement. 
   According to a development of the invention which is independent of a specific drive, the bristle carriers are each mounted on the brush-head carrier such that they can be moved about or along a movement axis in a direction transverse to the longitudinal direction of the toothbrush, each bristle carrier having its own movement axis, and these being spaced apart from one another. The toothbrush head is thus distinguished in that two bristle carriers which are mounted such that they can be moved about separate transverse axes are driven by a common drive-transmitter element, which can execute any desired drive movements. Irrespective of the actual design of the drive-transmitter element, such a toothbrush-head configuration has particular advantages in respect of effective teeth cleaning. 
   In particular, it is possible to provide two bristle carriers. A main bristle carrier, which may be arranged at that end of the brush-head carrier which is remote from the hand part of the toothbrush, is preferably mounted such that it can be rotated about an axis of rotation arranged essentially perpendicularly to the longitudinal direction of the toothbrush and essentially parallel to the main direction of the bristles provided on the main bristle carrier, and can be driven in oscillation by the drive rocker. The main bristle carrier may be of essentially plate-like design and have a circular contour. It can preferably be driven in a rotationally oscillating manner about its axis of symmetry. The rotationally oscillating drive movement may be combined, if appropriate, with a picking movement along the axis of rotation of the main bristle carrier, in order to achieve more thorough cleaning of the spaces between the teeth. It is possible, for this purpose, for the main bristle carrier to be mounted on the brush-head carrier such that it can be displaced in the direction of its axis of rotation. 
   Preferably provided alongside the main bristle carrier is an additional bristle carrier, which is arranged in the immediate vicinity behind the main bristle carrier, that is to say closer towards the hand part of the toothbrush. The additional bristle carrier may have different movement axes. According to a preferred configuration of the invention, the additional bristle carrier is mounted such that it can be pivoted about a pivot axis arranged essentially perpendicularly to the longitudinal direction of the toothbrush, and can be driven in oscillation by the drive rocker, which also drives the main bristle carrier. 
   According to one configuration of the invention, the pivot axis is arranged eccentrically in relation to the additional bristle carrier, or the bristle arrangement thereon, in order to achieve greater movement on a section of the bristle carrier which is located opposite the pivot axis. The pivot axis of the additional bristle carrier may be arranged approximately parallel to the main direction of the bristles, and thus parallel to the axis of rotation of the main bristle carrier. If the axis is arranged in the longitudinal direction of the toothbrush on a border section of the additional bristle carrier, the opposite border section of the additional bristle carrier executes a transversely reciprocating movement. It would also be possible, in principle, for the pivot axis to be arranged centrally in relation to the additional bristle carrier, with the result that the latter, in a manner similar to the main bristle carrier, itself rotates. It is preferable, however, for the pivot axis to be arranged, as described above, in particular at that end of the additional bristle carrier which is directed towards the hand part, with the result that the bristles which are adjacent to the main bristle carrier, and are fastened on the additional bristle carrier, can reciprocate transversely in the lateral direction and clean out the spaces between the teeth. 
   In an alternative development of the invention, it is possible for the pivot axis of the bristle carrier to be located essentially in the plane defined by the additional bristle carrier and to extend perpendicularly to the longitudinal direction of the toothbrush. The additional bristle carrier, accordingly, executes an up and down rocking movement, with the result that its clusters of bristles move up and down with picking action. This rocking axis of the additional bristle carrier can extend approximately centrally in relation to the longitudinal extent of the additional bristle carrier, in the longitudinal direction of the toothbrush, with the result that the rear end and the front end of the additional bristle carrier rock up and down in opposite directions. In an alternative configuration of the invention, it is also possible for the rocking axis of the additional bristle carrier to be displaced in the direction of one end of the additional bristle carrier. In particular, the additional bristle carrier may be mounted on the brush-head carrier such that it can be rocked about its end which is directed towards the hand part, with the result that the clusters of bristles which are adjacent to the main bristle carrier, and are fastened on the additional bristle carrier, execute an up and down picking movement. It is thus possible for the spaces between the teeth which are adjacent to tooth flanks treated by the bristle arrangement of the main bristle carrier to be cleaned particularly effectively. 
   It is not absolutely necessary, however, for the additional bristle carrier to be mounted in a pivotable manner. According to an advantageous configuration of the invention, it may be provided that the additional bristle carrier is mounted on the brush-head carrier such that it can be displaced in a translatory manner along a movement axis. The corresponding sliding guide of the additional bristle carrier preferably has a degree of freedom in a direction transverse to the longitudinal direction of the toothbrush. 
   In order for it to be possible, using the bristles arranged on the additional bristle carrier, to execute a picking movement in the longitudinal direction of the bristles, the translatory movement axis of the additional bristle carrier may be located essentially perpendicularly to the plane defined by the additional bristle carrier, i.e. essentially parallel to the main bristle direction defined by the bristles. As an alternative to this, the movement axis may be located transversely to the longitudinal direction of the toothbrush in the plane defined by the additional bristle carrier, with the result that the additional bristle carrier can be made to reciprocate transversely. It is thus possible for the bristles arranged on the additional bristle carrier to be moved in the direction of the spaces between the teeth and to clean these spaces out correspondingly. 
   The drive couplings between the two bristle carriers and the drive rocker are preferably designed as an articulated connection, each of which has an articulation axis in a direction transverse to the longitudinal direction of the toothbrush. Insofar as the drive rocker, rather than reciprocating in a translatory manner, executes a pivoting movement at its coupling points to the bristle carriers, it is possible for the articulated connection between the bristle carriers and the drive rocker to compensate for the corresponding angle offset. 
   In a development of the invention, the articulated connections between the drive-transmitter element and the bristle carriers, in addition to their articulation capability, have at least one further degree of freedom. In particular, the drive couplings of the bristle carriers are designed to transmit exclusively forces and movements transversely to the longitudinal direction of the toothbrush. No forces are transmitted in the longitudinal direction of the toothbrush. This makes it possible, on the one hand, to compensate for the relative movements, between the drive rocker and the bristle carriers, in the longitudinal direction of the toothbrush and, on the other hand, to exchange the toothbrush head in a straightforward manner. This is because the brush-head carrier preferably has releasable fastening means for fastening it on the hand part of the toothbrush, with the result that the brush-head carrier, together with the bristle carriers, can be removed from the hand part and/or positioned thereon. The drive couplings preferably have cutouts and/or engagement surfaces which, when the toothbrush head is plugged on, are introduced axially onto the drive-transmitter element on the hand part and/or the drive rocker. The drive couplings are preferably provided directly on the bristle carriers, i.e. the toothbrush head may be designed to be free of dedicated drive shafts, rockers or rods, the drive rocker, which is provided on the hand part, being introduced directly into a cutout in the additional bristle carrier and in the main bristle carrier and/or being brought into engagement with engagement surfaces of the additional bristle carrier and of the main bristle carrier, when the toothbrush head is plugged onto the hand part of the toothbrush. 
   In order to allow coupling to a drive rocker which can be rocked in relation to a plurality of axes and executes a double-cone-shaped drive movement, and in the process for the drive movement only to be partially transmitted to the bristle carriers, the articulated connection between the drive rocker and the bristle carriers may have a degree of freedom in a direction transverse to the longitudinal direction of the toothbrush. It is possible, in particular, for the connection between the drive rocker and the additional bristle carrier and/or the main bristle carrier to be designed to move freely in a direction transverse to the movement plane in which the respective bristle carrier is intended to move. Accordingly, the drive rocker, which moves in the form of a double cone, transmits just one component of its circulatory movement to the respective bristle carrier. If, for example, the additional bristle carrier is to be pivoted about an axis in a direction perpendicular to the additional bristle carrier, i.e. parallel to the bristles, the drive rocker may be seated in a longitudinal slot parallel to the bristle direction in the additional bristle carrier. The movement component transverse to the longitudinal direction of the bristles is transmitted to the bristle carrier, while the movement component of the drive rocker parallel to the longitudinal direction of the bristles is not transmitted. If, in contrast, the additional bristle carrier is to be rocked up and down, then the drive rocker may be seated in a transverse slot parallel to the bristle-carrier plane, with the result that the corresponding section is moved up and down, but the transversely reciprocating movement is not transmitted. 
   It is not necessary, however, for the drive rocker to be seated in a slot-like cutout in the additional bristle carrier. As an alternative, the additional bristle carrier may have, as drive coupling, a sliding surface which extends transversely to the longitudinal direction of the toothbrush and on which the drive rocker slides. It is preferably possible here to provide a prestressing device, for example in the form of a spring, which pushes the additional bristle carrier, by way of its sliding surface, onto the drive rocker and keeps it in engagement therewith. It is also possible, if appropriate, to dispense with such prestressing since, for example when the additional bristle carrier is to be rocked up and down with a picking movement, the additional bristle carrier is automatically pushed onto the drive rocker by the teeth-cleaning reaction forces. 
   If a drive rocker which circulates in the form of a double cone is provided, the engagement sliding surface of the additional bristle carrier may be of essentially planar design. In this case, the drive movement of the drive rocker has two mutually perpendicular components, with the result that the drive rocker slides back and forth on the sliding surface and, at the same time, pushes perpendicularly against the sliding surface and moves the bristle carrier correspondingly. 
   If, in contrast, a drive rocker which rocks in relation to one axis is provided, it is possible for the sliding surface to have a cam-like convexity in a direction transverse to the movement direction of the drive rocker. If the drive rocker moves in a reciprocating manner over the sliding surface, the cam-like convexity here produces the desired movement in the direction perpendicular to the reciprocating movement. If the drive rocker mounted on one axis rocks in the plane in which the bristle carrier is also to be moved, the engagement surface may be a straightforward bearing means. 
   In order to utilize the driven movement of the two bristle carriers, or of the bristle arrangements thereon, to better effect and to render teeth cleaning even more effective, a plurality of groups of clusters of bristles which are inclined in different directions may be arranged on the main bristle carrier and/or on the additional bristle carrier. It is possible here for the groups of clusters of bristles which are inclined in different directions to have different cross sections and/or to be designed with different properties, such as different stiffnesses, bristle lengths, bristle heights and the like. The clusters of bristles arranged on the main bristle carrier are preferably inclined in different directions to the clusters of bristles on the additional bristle carrier. According to one configuration of the invention, differently inclined clusters of bristles may be provided on each bristle carrier. 
   It has proven expedient here to provide not just clusters of bristles with a circular cross section, but also clusters of bristles with a non-circular cross section, in particular with an elongate, oval or rectangular cross section. 
   In one embodiment, the main bristle carrier and/or on the additional bristle carrier include clusters of bristles having free working ends which are located at different heights above the bristle carriers to improve penetration into interstitial spaces between the teeth and enhance the cleaning action of the brush. 
   Further advantages, possible applications and advantageous features of the invention can be gathered from are set forth in the following description of exemplary embodiments of the invention, which are illustrated in the figures of the drawing. In this case, all the features described or illustrated form, alone or in any desired expedient combination, the subject matter of the invention, irrespective of how they are summarized in the patent claims or how they relate back to preceding claims, and irrespective of how they are worded in the description or illustrated in the drawing. 

   
     DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a longitudinal section through an electric toothbrush with an exchangeable toothbrush head according to a first preferred configuration of the invention, 
       FIG. 2  shows a perspective plan view, in detail form, of the toothbrush head from  FIG. 1 , this showing two bristle carriers which are mounted in a moveable manner and are both mounted, and can be driven, such that they can be pivoted in each case about a pivot axis parallel to the main bristle direction, 
       FIG. 3  shows a perspective view, in detail form, of the toothbrush head from  FIG. 2  showing the drive mechanism and, in particular, the coupling of the rear, additional bristle carrier to a drive rocker, 
       FIG. 4  shows a perspective view, in detail form, of a toothbrush head with two moveably mounted bristle carriers according to a further configuration of the invention, in which case the rear, additional bristle carrier is mounted, and can be driven, such that it can be rocked up and down about a transverse axis at its rear end section, 
       FIG. 5  shows a perspective view, in detail form, of the toothbrush head from  FIG. 4  in a different viewing direction, this showing the drive mechanism for the two bristle carriers and, in particular, the coupling of the rear, additional bristle carrier to a drive rocker, 
       FIG. 6  shows a perspective view, in detail form, of a toothbrush head with two moveably mounted bristle carriers according to an alternative configuration of the invention, in which case the rear, additional bristle carrier is mounted approximately centrally such that it can be rocked about a transverse axis, 
       FIG. 7  shows a perspective view, in detail form, of the toothbrush head from  FIG. 6  in a different viewing direction, this showing the drive mechanism for the two bristle carriers and, in particular, the coupling of the rear, additional bristle carrier to the drive rocker of the drive, 
       FIG. 8  shows a perspective view, in detail form, of a toothbrush head with two moveably mounted bristle carriers according to an alternative configuration of the invention, in which case the rear, additional bristle carrier is mounted such that it can be moved up and down about a translatory movement axis essentially parallel to the main bristle direction, 
       FIG. 9  shows a perspective view, in detail form, of the toothbrush head from  FIG. 8  in a different viewing direction, this showing the drive mechanism for the two bristle carriers and, in particular, the coupling of the rear, additional bristle carrier to the drive rocker of the drive, 
       FIG. 10  shows a perspective view, in detail form, of a toothbrush head with two moveably mounted bristle carriers according to a further configuration of the invention, in which case the rear, additional bristle carrier is mounted such that it can be moved up and down about a translatory movement axis in a direction transverse to the longitudinal direction of the toothbrush and transverse to the main bristle direction, 
       FIG. 11  shows a perspective view, in detail form, of the toothbrush head from  FIG. 10  showing the drive mechanism for the two bristle carriers and, in particular, the coupling of the rear, additional bristle carrier to the drive rocker, 
       FIG. 12  shows a perspective view of a toothbrush head of the toothbrush from  FIG. 1  showing the arrangement of the clusters of bristles on the two bristle carriers, 
       FIG. 13  shows a cross section through the axis of rotation of the main bristle carrier from  FIG. 12  along line B-B in  FIG. 14 , and 
       FIG. 14  shows a longitudinal section through the toothbrush head from  FIG. 12 . 
   

   DETAILED DESCRIPTION 
   The toothbrush shown in  FIG. 1  comprises a hand part  1  and a toothbrush head  2  which is seated on a brush tube  3 , which forms an end of the hand part  1  or is connected thereto. The hand part  1  is formed by a toothbrush housing  4  in which a battery-accommodating compartment and a drive motor  5  are arranged axially one behind the other. 
   The brush head  2  has two bristle arrangements, namely a main bristle arrangement  9 , which is located directly at the head end, and a rear, additional bristle arrangement  8 , which is located in the immediate vicinity of the main bristle arrangement  9 , on the side of the latter which is directed towards the hand part  1 . 
   As  FIG. 2  shows, the bristle arrangement, which is located at the head end, is borne by a main bristle carrier, which is designed approximately in the form of a circular plate in the direction of the bristle arrangement and is fastened on a brush-head carrier  11 . As  FIG. 13  shows, the bristle carrier  10  is fitted in a rotatable manner on an axis of rotation  12  which is anchored in the brush-head carrier  11  and extends, perpendicularly to the longitudinal axis of the toothbrush, approximately parallel to the main bristle direction of the bristle arrangement  9 . The axis of rotation  12  forms the axis of symmetry of the plate-like bristle carrier  10 . 
   The bristle carrier  10  is driven in rotational oscillation about the axis of rotation  12  by the motor  5 , by means of a transmitter  14  in the form of a drive rocker  15 . The drive rocker  15  is a rectilinear, essentially rigid metal rod and is mounted, between the motor in the hand part  1  and the bristle carrier  10  in the brush tube  3 , in a bearing  16 , which may be designed as an elastic bearing plug in the form of a ring or of a sleeve. The bearing  16  allows the drive rocker  15  to pivot about axes which are located in a plane perpendicular to the longitudinal direction of the toothbrush. The drive rocker  15  is driven by an eccentric  17  which is seated in a rotationally fixed manner on the motor shaft, which extends in the longitudinal direction of the toothbrush (cf.  FIG. 1 ). The drive rocker  15  here executes a double-cone-shaped tumbling or circulatory movement, the vertices of the two cones being located approximately in the region of the bearing  16 . The two ends of the drive rocker  15  execute a circular-path movement in each case in a plane which is perpendicular to the longitudinal direction of the toothbrush. 
   That end of the drive rocker  15  which is directed towards the bristle carrier  10  is seated in a longitudinal-slot-like cutout  18  in the bristle carrier  10 , said cutout being formed in a circumferential surface of the bristle carrier  10  which is directed towards the hand part  1  and extending essentially parallel to the axis of rotation  12  (cf.  FIGS. 1 and 14 ). By virtue of the longitudinal-slot-like cutout, it is only the component of the drive movement of the drive rocker  15  in the direction transverse to the axis of rotation  12  which is transmitted to the bristle carrier  10 . The up and down movement, i.e. the component of the circulatory drive movement parallel to the axis of rotation  12 , is not transmitted since the drive rocker  15  can move freely parallel to the axis of rotation  12  in the cutout  18 . 
   As  FIG. 2  shows, the rear bristle arrangement  8 , which is closer to the hand part  1 , is borne by an approximately plate-like additional bristle carrier  13  which, like the main bristle carrier  10 , is mounted in a moveable manner on the brush-head carrier  11  independently of the drive transmitter  14 . As  FIG. 2  shows, the additional bristle carrier  13  is mounted at its rear edge section, which is directed towards the hand part, such that it can be pivoted about a pivot axis  19  which extends essentially perpendicularly to the longitudinal direction of the toothbrush, or essentially parallel to the axis of rotation  12  of the bristle carrier  10 , and perpendicularly to the plane defined by the additional bristle carrier  13 . Accordingly, it is possible for the additional bristle carrier  13 , in particular its section which is directed towards the main bristle carrier  10 , to pivot transversely back and forth in the lateral direction, as the arrow  20  illustrates. 
   In order to drive the additional bristle arrangement  8  in a rotationally oscillating manner about the pivot axis  19 , the additional bristle carrier  13  is coupled to the drive rocker  15 , which also drives the main bristle carrier  10 . As  FIG. 3  shows, there is provided, on the underside of the additional bristle carrier  13 , a drive coupling  21  which comprises a longitudinal cutout  22  which is parallel to the pivot axis  19  and in which the drive rocker  15  is guided. In the configuration depicted, the longitudinal cutout  22  is defined by two post-like protrusions  23  and  24 , between which the drive rocker  15  is guided. The protrusions  23 ,  24  extend essentially parallel to the pivot axis  19 , with the result that the cutout defined between the protrusions  23  and  24 , or the gap, likewise runs parallel to the pivot axis  19 . Accordingly, in this case too, just one component of the circulating drive movement of the drive rocker  15  is transmitted, namely in the plane parallel to the longitudinal direction of the toothbrush, in the direction perpendicular to the pivot axis  19 . The vertical component of the drive movement parallel to the plane of symmetry of the toothbrush is not transmitted, since the drive rocker can reciprocate freely in this direction in the longitudinal cutout  22  between the protrusions  23  and  24 . 
   Alternative mountings for the additional bristle arrangement  8  or the additional bristle carrier  13  are shown in  FIGS. 4 to 11 . The toothbrush heads shown here are likewise envisaged for the toothbrush shown in  FIG. 1  and otherwise correspond to the previously described toothbrush head so that, in this respect, you are referred to the description thereof and the same designations are used for corresponding components. 
   According to  FIG. 4 , the additional bristle carrier  13  is mounted on the brush-head carrier  11  such that it can be pivoted about a pivot axis  25  which extends essentially parallel to the plane defined by the additional bristle carrier  13 , or transversely to the axis of rotation  12  of the bristle carrier  10 , and runs transversely to the longitudinal direction of the toothbrush. The additional bristle carrier  13  here is mounted in a pivotable manner by way of its rear edge or end section, i.e. the one directed towards the hand part  1 , with the result that it can execute an up and down rocking movement about the pivot axis  25 . That section of the additional bristle carrier  13  which is directed towards the main bristle carrier  10  can rock up and down according to the arrow  26 , with the result that the bristles of the additional bristle arrangement  8  execute a picking movement. 
   In order to drive the additional bristle carrier  13  in oscillation about the pivot axis  25 , there is provided on its underside, as drive coupling, an engagement or sliding surface  27 , by means of which it is seated on the drive rocker  15 , which also drives the main bristle carrier  10 . As  FIG. 5  shows, the engagement or sliding surface  27  is formed by the end surface of an elongate tappet or protuberance  28  which extends transversely to the longitudinal direction of the toothbrush and projects in the direction of the drive rocker  15 . The surface of the tappet  28  may be of essentially planar design. The circulating drive rocker moves transversely over the sliding surface  27 , the vertical component of the circulating rocking movement being transmitted to the tappet or protuberance  28  and rocking the additional bristle carrier  13  up and down, the sliding surface  27  being kept in engagement with the drive rocker  15  by the teeth-cleaning reaction forces acting on the additional bristle arrangement. It is also possible here, if appropriate, to provide prestressing of the additional bristle carrier, for example by means of a spring, which pushes the additional bristle carrier against the drive rocker. As an alternative, it would also be possible, instead of providing the sliding surface  27 , to provide a groove-like transverse cutout in a corresponding section of the additional bristle carrier  13 , the drive rocker  15  being seated in said cutout, with the result that the drive rocker would push the additional bristle carrier upwards and pull it actively downwards. Such a transverse groove corresponds to the arrangement of two parallel sliding surfaces  27  between which the drive rocker  15  is guided. 
   According to  FIGS. 6 and 7 , it is also possible for the additional bristle carrier  13  to be mounted approximately centrally about a transversely running pivot axis  29  in the manner of a rocker. As in the abovedescribed configuration, the pivot axis  29  extends, transversely to the longitudinal direction of the toothbrush, or to the axis of rotation  12  of the bristle carrier  10 , approximately in the plane defined by the additional bristle carrier  13  or a plane parallel thereto, with the result that a section of the additional bristle carrier  13  which is directed towards the main bristle carrier  10  and an opposite section of the additional bristle carrier  13 , which is directed towards the hand part  1 , execute up and down rocking movements in opposite directions. The drive coupling of the additional bristle carrier may be formed, in a manner identical to the abovedescribed configuration according to  FIGS. 4 and 5 , by a sliding surface  27  which is provided on a tappet  28  and slides on the drive rocker  15 . In so far as the teeth-cleaning reaction forces act on both sides of the pivot axis  29  in this configuration, a prestressing device which keeps the additional bristle carrier in engagement with the drive rocker  15  may be expedient. It is also possible here, if appropriate, to provide the abovedescribed positive guidance by means of a transverse groove, in which the drive rocker is seated. 
   According to  FIGS. 8 and 9 , the additional bristle carrier  13  may also be guided such that it can be displaced in a translatory manner on the brush-head carrier  11 . As  FIG. 8  shows, the additional bristle carrier  13  may be guided along two movement axes  30  which extend essentially perpendicularly to the plane defined by the additional bristle carrier, or essentially parallel to the axis of rotation  12  of the bristle carrier  10 . The sliding guide may be formed, for example, by a cylindrical bolt guide which is known per se. The sliding-guide axes  30  may be arranged, on the longitudinal centre plane of the toothbrush, in a rear and front edge section of the additional bristle carrier  13 , as  FIG. 8  shows. In accordance with the translatory movement capability of the additional bristle carrier  13 , the latter can execute up and down stroke movements, with the result that the additional bristle arrangement  8  executes picking movements on the additional bristle carrier  13 . 
   Here too, the stroke movement of the additional bristle carrier  13  is produced by a coupling to the drive rocker  15 . As  FIG. 9  shows, it is possible to provide, on an underside of the additional bristle carrier  13 , a sliding surface  27  which extends transversely to the longitudinal direction of the toothbrush and is formed by the surface of a tappet  28  which projects in relation to the drive rocker  15 . The tappet  28  is expediently arranged approximately centrally beneath the additional bristle arrangement and centrally between the movement axes  30 , with the result that it is possible to produce a uniform force distribution and tilting-free movement. The teeth-cleaning reaction forces acting on the additional bristle arrangement  8  keep the sliding surface  27  in engagement with the drive rocker  15 . 
   A further possible mounting for the additional bristle carrier  13  is shown in  FIGS. 10 and 11 . Here too, the additional bristle carrier  13  is mounted such that it can be displaced in a translatory manner on the brush-head carrier  11 , to be precise along two parallel sliding-guide axes  31  which extend, in the plane defined by the additional bristle carrier  13 , transversely to the longitudinal direction of the toothbrush, or to the axis of rotation  12  of the bristle carrier  10 . As  FIG. 10  shows, a rear end section of the additional bristle carrier  13 , said section being directed towards the hand part  1 , and an end section of the additional bristle carrier  13  which is directed towards the main bristle carrier  10  may be mounted by the abovementioned sliding guide. In this case, the additional bristle carrier  13  can execute transversely reciprocating movements in the lateral direction, as the arrow  32  illustrates. 
   In this case too, the translationally oscillating drive movement of the additional bristle carrier  13  is produced by the drive rocker  15 . As  FIG. 11  shows, the additional bristle carrier  13  is seated on the drive rocker  15  by means of a transverse guide  33 . The transverse guide  33 , in a manner similar to the configuration of  FIGS. 2 and 3 , is defined by two parallel post-like protrusions  23  and  24  which, between them, define a gap or a longitudinal cutout  22  which extends essentially perpendicularly to the plane of the additional bristle carrier  13 . The drive rocker  15  can slide freely up and down in the vertical direction, i.e. in the longitudinal symmetry plane of the toothbrush, between the two protrusions  23  and  24 . The drive movement of the drive rocker  15 , however, is transmitted in a plane perpendicular thereto, i.e. in a plane parallel to the two sliding-guide axes  31 , with the result that the additional bristle carrier  13  reciprocates in oscillation in the direction of the sliding-guide axes  31 . 
   A preferred bristle covering of the two bristle carriers  10  and  13  is shown in  FIGS. 12 to 14 . It goes without saying that the bristle covering according to  FIGS. 12 to 14  may be provided for each of the abovedescribed embodiments of the additional bristle carrier and/or the mounting thereof. 
   The main bristle arrangement  9 , which can be driven in a rotationally oscillating manner, has an approximately circular-cylindrical outline overall and is formed by a plurality of clusters of bristles at different inclinations, of different heights and different cross sections. 
   As  FIG. 12  and  FIG. 13  show, central, first clusters of bristles  38  are arranged in the middle around the axis of rotation of the main bristle carrier. They extend perpendicularly to the plane defined by the bristle carrier  10  and have an approximately circular or slightly oval cross section. Four first clusters of bristles  38  are provided. They are located in the middle around the axis of rotation  12 . Adjacent to the first cluster of bristles  38  are second clusters of bristles  39 , which, when the bristle carrier  10  has not been rotated, are located on the longitudinal centre axis of the toothbrush and in front of, and behind, the first cluster of bristles  38 , as seen in the longitudinal direction. As  FIG. 12  shows, the second clusters of bristles  39  have an oval cross section with a longitudinal axis extending transversely to the longitudinal axis of the toothbrush. The second clusters of bristles  39  are likewise arranged perpendicularly to the plane defined by the bristle carrier  10 . They are spaced apart from the axis of rotation  12  by a greater distance than the first clusters of bristles  38 . The ratio of contour length to contour width is approximately two. 
   The rest of the clusters of bristles of the driven bristle arrangement are inclined, to be precise in different directions. The fourth clusters of bristles  40 , which are arranged radially outside the first clusters of bristles  38 , as it were on a second bristle-cluster ring, have an approximately circular cross section and are inclined radially outwards, i.e. their free working ends are further away from the axis of rotation of the bristle carrier than their fastening sections fastened on the bristle carrier  10 . The angle of inclination is acute and less than 20°. 
   The third clusters of bristles  41  are likewise inclined radially outwards. However, they have an oval contour or an elongate cross section, the longitudinal axis of the cross section being oriented radially. The cross section of the third clusters of bristles is approximately twice to three times as long as it is wide. The third clusters of bristles  41  are seated radially outside the first clusters of bristles  38 , adjacent to the latter, on a bristle-arrangement axis of symmetry running transversely to the longitudinal direction of the toothbrush. 
   The remaining clusters of bristles of the bristle arrangement  9  are likewise inclined, albeit in the circumferential direction about the axis of rotation  12 . They form the outer edge or ring of the bristle arrangement  9 . 
   The fifth clusters of bristles  42  have an oval contour or an elongate cross section, which is oriented approximately tangentially to the edge of the bristle carrier  10 . In cross section, the clusters of bristles  42  are approximately twice to three times as long as they are wide. As  FIG. 12  shows, the fifth clusters of bristles  42  are arranged in pairs in the region of the longitudinal axis of the toothbrush if the bristle arrangement  9  has not been rotated. They are inclined towards one another in pairs, with the result that their free working ends are closer together than their fastening sections anchored in the bristle carrier  10 . 
   Finally, sixth clusters of bristles  43  are provided, these likewise being located on the outer edge of the bristle arrangement and being inclined in the circumferential direction about the axis of rotation  12 . However, they have an approximately circular cross section and are arranged in pairs on both sides of the third clusters of bristles  41  and are likewise inclined towards the latter in opposite directions. The angles of inclination of the circumferentially inclined clusters of bristles  43  and  42  located on the outside are likewise acute and preferably less than 20° to the vertical through the plane defined by the bristle carrier  10 . 
   As  FIGS. 13 and 14  show, the clusters of bristles arranged on the moveable bristle carrier  10  have two lengths. The outer, fifth clusters of bristles  42 , which are located right at the front and rear, as seen in the longitudinal direction, and of which the free ends are all located in a single plane, are longer than the rest of the clusters of bristles. The free ends of the fifth clusters of bristles  42  define a plane. The difference in height between the clusters of bristles is in the range of from 0.5 mm to 2.5 mm, preferably approximately 1.0 mm to 1.5 mm. In the configuration depicted, it is 1.2 mm. 
   The clusters of bristles of the additional bristle arrangement  8  likewise have different cross sections, in terms of contour and surface area, and, furthermore, are likewise inclined differently. Clusters of bristles of different lengths are also provided, as is yet to be described. 
   As  FIG. 12  shows, roughly speaking three rows of clusters of bristles, all extending approximately in the longitudinal direction of the toothbrush, are provided in the additional bristle arrangement. The central row is located on the longitudinal centre axis of the additional bristle carrier  13 , while the two outer rows are spaced apart transversely therefrom. 
   In the central row of bristles, all the clusters of bristles are inclined in the direction of the hand part  1 . All the clusters of bristles have an elongate or oval cross section, but different cross-sectional surface areas. First clusters of bristles  44  of the fixed bristle arrangement  8  have an oval cross section, of which the longitudinal axis is approximately double the length of the transverse axis. The first clusters of bristles  44  alternate in the central row with clusters of bristles  45 , which are referred to hereinbelow as fourth clusters of bristles and are likewise inclined rearwards in the direction of the hand part. The fourth clusters of bristles  45  likewise have an oval cross section, but are of considerably narrower design and have a smaller cross-sectional surface area than the first clusters of bristles. In accordance with the configuration depicted, the elongate cross section is approximately—roughly speaking—three times as long as it is wide. The length of the oval cross section here is slightly smaller than the length of the cross section of the first clusters of bristles  44 . 
   The two outer rows of the clusters of bristles of the fixed bristle arrangement  8  comprise second and third clusters of bristles. Second clusters of bristles  46  have an oval cross section with a relatively narrow contour. The longitudinal axis of the elongate cross-sectional contour is approximately three times the width of the cross-sectional contour. The third clusters of bristles  47  have an approximately circular cross section, the diameter of the cross section being somewhat more than half the longitudinal axis of the cross section of the second clusters of bristles  46 . As  FIG. 12  shows, the third clusters of bristles  47  are spaced apart differently from the longitudinal centre axis of the brush head  2 . The distance from the longitudinal centre axis decreases in the direction of the hand part  1 . The third clusters of bristles  47 , however, are still located one behind the other to the extent that their contour is located approximately behind the contour of the much wider, second clusters of bristles  46 . The second and third clusters of bristles  46  and  47  are each inclined forwards, i.e. in the direction of the drivable bristle arrangement  9 , at an acute angle, to be precise at an acute angle which may be preferably 12° to 15°. All the clusters of bristles of the additional bristle arrangement  8  are preferably inclined in the longitudinal centre plane of the brush head  2  or planes which are parallel thereto. In contrast, all the clusters of bristles of the main bristle arrangement  9  are inclined differently or in a different direction. 
   The clusters of bristles of the additional bristle arrangement  8  define two working planes, as  FIG. 14  shows. The circular, third clusters of bristles  47  in the outer rows and the thicker, first clusters of bristles  44  in the central row are of shorter design and define, with their free working ends, a lower-level plane which coincides with the plane which is defined by the first, second, third, fourth and sixth clusters of bristles of the main bristle arrangement  9 . A higher, second plane, in contrast, is defined by the longer, fourth clusters of bristles  45  in the central row and the second clusters of bristles  46  in the two outer rows. This higher plane coincides with the plane which is defined by the longer, fifth clusters of bristles of the main bristle arrangement  9 . In the additional bristle arrangement  8 , it is thus the case that the narrower, oval clusters of bristles are longer than the thicker clusters of bristles. 
   In contrast to the main bristle arrangement  9 , the additional bristle arrangement  8 , rather than having a circular contour, has an elongate contour overall which, at its end which is directed towards the rotating bristle arrangement  9 , encloses the latter. 
   As  FIG. 1  shows, the brush head  2  is fastened in a releasable manner on the brush tube  3 . It can easily be drawn off from the brush tube  3 , and pushed onto the same, in the axial direction. For this purpose, the brush-head carrier  11  has a fastening section  34  by means of which it can be pushed onto or into a corresponding fastening section  35  at the end of the brush tube  3 . The two fastening sections  34  and  35  are both designed approximately in the form of half-shells in each case and supplement one another in a precisely fitting manner, with the result that, in the pushed-together state, they form a hollow profile which continues the brush tube  3 . 
   In order to secure the brush head  2  in the axial direction on the hand part  1  and/or the brush tube  3 , there is provided, between the brush-head carrier and the hand part  1 , a latching device  36  which, when the brush head  2  is pushed on, latches automatically in the axial direction and, on the other hand, can be released again by radial pressure being applied to the brush tube  3  or the brush-head carrier. When the brush head  2  is pushed on, the drive rocker  15  is automatically coupled, at the same time, to the two moveable bristle carriers  10  and  13 .