Patent Publication Number: US-6708364-B1

Title: Flexible brush head for a toothbrush

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to a flexible brush head for a toothbrush. 
     The object of the present invention is to provide a flexible, adaptable brush head which allows better cleaning of the teeth as a whole. 
     BRIEF SUMMARY OF THE INVENTION 
     The design of the brush head according to the invention makes it very flexible. It has a bristle carrier which is made of a first, hard but elastic plastic and is divided up into at least two segments, which are located one behind the other along the longitudinal axis of the brush head, by at least one recess, which passes through the bristle carrier, in the form of a tunnel, transversely with respect to the longitudinal axis of the brush head. 
     The segments of the bristle carrier, and preferably also the tunnel, extend over the entire width of the brush head, the tunnel preferably being filled with a second, rubber-elastic plastic, which is much softer than the first plastic of the bristle carrier, with the result that there is no risk of the tunnel being contaminated. The design described allows the individual segments of the bristle carrier to be deflected with respect to one another, which results in the brush head being flexible. Since the brush head can bend about an axis running transversely with respect to the longitudinal axis of the brush head, adaptation both to the outsides and the insides of the teeth is possible, this allowing more careful cleaning of the teeth, of the spaces between the teeth and of the gum line. Slight turning of the individual segments of the bristle carrier with respect to one another, that is to say slight torsion of the brush head, is also possible, this further improving adaptation of the brushing surface, which is produced by the bristles or bristle clusters, to the shapes of the individual teeth and of the teeth as a whole, and thus further improving the cleaning operation. If the brush head is subjected to pronounced or excessive pressure, it bends to a correspondingly more pronounced extent and thus compensates for some of the pressure. This means that gentler and more careful cleaning is possible. 
     If the brush head has more than just two segments and, accordingly, more than one tunnel, then the flexibility of the brush head increases and the effects outlined are enhanced. 
     The flexibility of the brush head can be increased further if the regions of the bristle carrier which bound the tunnels on the bristle-carrying side of the bristle carrier and on the side which is located opposite the bristle-carrying side of the bristle carrier are configured such that they can be expanded and/or compressed in the longitudinal direction of the brush head. In order to achieve greater stability of the brush head, it is expedient for these regions to be configured in the expansible form described just on one side in each case, and advantageously on the bristle-carrying side. A configuration in the form of a web which is folded in the manner of an accordion is particularly suitable. A bristle-carrier region which is configured in expansible form with or without folding and bounds the tunnel of said sides yields elastically to its limit of expansion and thus acts as a bending-limiting means. When the limit of expansion is reached, further deflection or turning of the segments with respect to one another is only possible by force being applied. Automatic return of the segments into their original position is effected predominantly by the elastic restoring action of said bristle-carrier regions which bound the tunnels, and also by the second, soft, elastic plastic, with which the tunnel is filled and which is joined firmly to the first, hard, elastic plastic of the bristle carrier. 
     For producing a brush head of the type described, it is advantageous if, for the case where more than one tunnel is provided in the brush head, the tunnels are connected to one another, since it is easier in this way for them to be filled with the second, soft, rubber-elastic plastic. If the intention is to produce entire toothbrushes, then it is advantageous to form the brush head integrally on a brush handle or a plug-on part and to produce said handle or plug-on part likewise from the first, hard but elastic plastic. 
     Further advantageous embodiments of the brush head and toothbrushes with brush heads according to the invention are seen in the several drawing figures and are described herein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the brush head according to the invention are explained hereinbelow with reference to the drawings. 
     The various figures, numbered  1  to  5 , each show, purely schematically, a toothbrush, consisting of two different plastic materials, with part of a brush handle and with in each case a different embodiment of the brush head according to the invention, the illustrations of the individual figures being as follows: 
     FIG. 1 a  shows a plan view of the bristle-carrying side of such a toothbrush; 
     FIG. 1 b  shows a side view of the toothbrush illustrated in FIG. 1 a;    
     FIG. 1 c  shows a view of the rear side, which is located opposite the bristle-carrying side, of the toothbrush illustrated in FIGS. 1 a  and  1   b;    
     FIG. 1 d  shows a longitudinal section along the line I—I in FIG. 1 a;    
     FIG. 1 e  shows a section through the brush handle along the line II—II in FIG. 1 b;    
     FIG. 1 f  shows a section through the brush head along the line III—III in FIG. 1 b;    
     FIG. 1 g  shows a section through the brush head along the line IV—IV in FIG. 1 b;    
     FIG. 2 a  shows a toothbrush with a further embodiment of the brush head according to the invention and with the transition to a brush handle in the plan view of the bristle-carrying side; 
     FIG. 2 b  shows a side view of the toothbrush illustrated in FIG. 2 a;    
     FIG. 2 c  shows a section through the brush head along the line I—I in FIG. 2 b , the bristle clusters not being illustrated; 
     FIG. 2 d  shows a side view of the core of the toothbrush illustrated in FIGS. 2 a  and  2   b , said core consisting of the first, hard but elastic plastic; 
     FIG. 2 e  shows an illustration, analogous to FIG. 2 d , where the toothbrush shown in FIGS. 2 a  and  2   b  is subjected to bending stress; 
     FIG. 3 a  shows a toothbrush with a further embodiment of the brush head according to the invention and with the transition to a brush handle in the plan view of the bristle-carrying side; 
     FIG. 3 b  shows a side view of the toothbrush illustrated in FIG. 3 a;    
     FIG. 3 c  shows a side view of the core of the toothbrush illustrated in FIGS. 3 a  and  3   b , said core consisting of the first, hard but elastic plastic; 
     FIG. 3 d  shows a section along the line I—I in FIG. 3 a;    
     FIG. 3 e  shows a section along the line II—II in FIG. 3 c;    
     FIG. 3 f  shows an enlarged illustration of a tunnel, and of the bristle-carrier regions bounding it, according to FIG. 3 c;    
     FIG. 3 g  shows the enlarged region of FIG. 3 f  in a section along the center longitudinal axis of the brush head; 
     FIG. 4 a  shows a toothbrush with a further embodiment of the brush head according to the invention and with the transition to a brush handle in the plan view of the bristle-carrying side; 
     FIG. 4 b  shows a side view of the toothbrush illustrated in FIG. 4 a;    
     FIG. 4 c  shows a view of the rear side, which is located opposite the bristle-carrying side, of the toothbrush illustrated in FIGS. 4 a  and  4   b;    
     FIG. 4 d  shows a longitudinal section along the line I—I in FIG. 4 a;    
     FIG. 4 e  shows a section through the brush handle along the line II—II in FIG. 4 b;    
     FIG. 4 f  shows a section through the brush head along the line III—III in FIG. 4 b;    
     FIG. 4 g  shows a section through the brush head along the line IV—IV in FIG. 4 b;    
     FIG. 5 a  shows a toothbrush with a further embodiment of the brush head according to the invention, said embodiment being analogous to the brush head shown in FIGS. 2 a  to  2   e , in an illustration corresponding to that in FIG. 2 d;    
     FIG. 5 b  shows an illustration where the toothbrush illustrated in FIG. 5 a  is subjected to bending stress; and 
     FIG. 6 is an enlarged side elevation of a further modified form of the invention wherein the side-to-side tunnels through the brush head are bounded at the top and bottom by flexible accordion-like pleats. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1 a-g  show a toothbrush  10  with part of a brush handle  12  and a brush head  14  with a bristle carrier  16 . The bristle carrier  16 , which consists of a first, hard but elastic plastic, is subdivided into five segments  17  (FIGS. 1 a ,  1   d ) by tunnels  20 , which pass through the bristle carrier  16  over its entire width, different numbers of rows of bristles combined to form bristle clusters  18  being anchored in said five segments. The segments  17  of the bristle carrier  16  extend, as do the tunnels  20 , over the entire width b of the brush head  14  in each case (FIGS. 1 f ,  1   g ). The tunnels  20  between the segments  17  of the bristle carrier  16  (FIGS. 1 d ,  1   g ) are filled with a second, soft, rubber-elastic plastic, which is joined firmly to the first, hard, elastic plastic of the bristle carrier  16 . The tunnels  20  are thus entirely surrounded by the hard, elastic plastic of the bristle carrier  16 . On the bristle-carrying side of the brush head  14  and on that side of the brush head  14  which is located opposite the bristle-carrying side, the tunnels are bounded by regions  22  of the bristle carrier  16 , said regions being web-like and of thin design and thus being very flexible. 
     In the center of its sides forming the lateral border of the brush head  14 , the bristle carrier  16  has a lateral groove  30  which is the same height as the tunnels  20  (FIGS. 1 b ,  1   e ,  1   f ). The tunnels  20  are connected to one another via the lateral groove  30 , which runs more or less around the entire brush head  14  and is likewise filled with the second, soft, rubber-elastic plastic. 
     The brush head  14  and brush handle  12  are connected integrally to one another via the segment  17 ′ of the bristle carrier  16 , said segment  17 ′ being adjacent to the brush handle  12 , it being the case that the brush handle  12  likewise consists of the hard but elastic plastic of the bristle carrier  16  (FIGS. 1 a  to  1   d ). The brush handle  12  has a handle groove  26  which extends, on the bristle-carrying side of the toothbrush  10 , along the longitudinal axis  24  of the toothbrush  10  (FIG. 1 a ). Just in front of the brush head  14 , this handle groove  26  divides (FIG. 1 a ) and runs obliquely toward the brush head  14  along the lateral sides of the brush handle  12  and merges into the lateral groove  30  (FIG. 1 b ). In the same way as the lateral groove  30 , the handle groove  26  is filled with the second, soft, rubber-elastic plastic. 
     As a result of the large number of segments  17 , into which the bristle carrier  16  is subdivided by the tunnels  20 , and on account of the relatively thin and thus very flexible regions  22  of the bristle carrier  16 , the brush head  14  as a whole is very flexible and can easily be bent and turned with torsional movement along the center longitudinal axis  24 ′ of the brush head  14 . This achieves better adaptation of the brushing surface to the curves of the teeth and the spaces between the teeth as well as better cleaning. The tunnels  20  thus increase the flexibility of the brush head  14 . However, at the same time, the regions  22  of the bristle carrier  16 , which bound the tunnels  20  on the bristle-carrying side of the brush head  14  and on that side of the brush head  14  which is located opposite the bristle-carrying side, reduce the risk of part of the brush head  14  being bitten off during use. 
     The integral connection between the brush handle  12  and brush head  14  and the connection of the tunnels  20  to one another via the lateral groove  30  of the bristle carrier  16  permit, together with the connection of the lateral groove  30  and handle groove  26 , very straightforward production of the entire toothbrush with the brush head  14  according to the invention by two-component injection molding. 
     An embodiment which is modified slightly with respect to the embodiment outlined in FIGS. 1 a  to  1   g  is illustrated in FIGS. 2 a  to  2   e.    
     The embodiment illustrated in FIGS. 2 a  to  2   e  shows a toothbrush  10  with a further embodiment of the brush head  14  and with a short section of a brush handle  12 . The brush head  14 , which has a bristle carrier  16  subdivided into three segments  17  by tunnels  20 , is formed integrally on the brush handle  12  (FIG. 2 a ). The first segment  17 ′ of the bristle carrier  16 , the segment  17 ′ being adjacent to the brush handle  12  and also having a number of bristle clusters  18  anchored in it, forms a transition region  32  to the brush handle  12 . 
     As in the embodiment illustrated in FIGS. 1 a  to  1   g , it is also the case here that tunnels  20  are located between the segments  17  of the bristle carrier  16 , which extend over the entire width of the brush head  14 , said tunnels  20  likewise extending over the entire width of the brush head  14  (FIGS. 2 a ,  2   b ,  2   d ,  2   e ) and being filled with the second, soft, rubber-elastic plastic. 
     As in the embodiment shown in FIGS. 1 a  to  1   g , it is also the case here that a lateral groove  30 , which is made in the side of the bristle carrier  16  and is filled with the soft, elastic plastic, connects the tunnels  20  to one another. For the purpose of straightforward production, the integrally formed brush handle  12  also has a groove  26  on the two lateral surfaces, the groove merging into the groove  30  of the bristle carrier  16  in the transition region  32  (FIGS. 2 b ,  2   d  and  2   e ) and being filled with the second, soft, rubber-elastic plastic. 
     FIGS. 2 d  and  2   e  show just the core, which consists of the first, hard but elastic plastic, i.e. the filling of the tunnels  20  and of the grooves  26  and  30  made of the second, rubber-elastic plastic is not illustrated. 
     The tunnels  20  are entirely surrounded by the first, hard, elastic plastic of the bristle carrier  16 . The regions  22  of the bristle carrier  16 , which bound the tunnels  20  on the bristle-carrying side of the toothbrush  10  (FIGS. 2 b ,  2   d ,  2   e ), are very thin and of slightly curved design (FIGS. 2 b ,  2   c ), with the result that they appear on the bristle-carrying side of the brush head  14  as hollowed channels (FIG. 2 a ). Under use-induced loading, these slightly curved regions  22  of the bristle carrier  16  extend (FIG. 2 d ) and, in the fully stressed state, resist any further bending of the bristle carrier  16  (FIG. 2 e ). The regions  22  of the bristle carrier  16  which are formed in this way thus, on the one hand, increase flexibility and, on the other hand, act as a bending-limiting means, which prevents excessive bending of the brush head. 
     The regions  22 ′ of the bristle carrier  16 , which bound the tunnels  20  on the side which is located opposite the bristle-carrying side, are likewise thin and elastic, with the result that they are compressed elastically when the bristle carrier  16  is bent during use of the toothbrush, as is illustrated in FIG. 2 e.    
     The bristle clusters which are designated by  18 ′ in FIGS. 2 b ,  2   d  and  2   e  and belong to the rows adjacent to the tunnels  20  are positioned obliquely. As FIGS. 2 b ,  2   d  and  2   e  show, the oblique positioning is such that the bristle clusters  18 ′, which are each arranged on both sides of a tunnel  20 , are inclined toward one another, thus covering over the tunnel region located therebetween (FIGS. 2 b  and  2   d ). Those receiving holes which are formed in the segments  17  of the bristle carrier  16  and are intended for the bristle clusters  18 ′ are correspondingly positioned obliquely. 
     The embodiment illustrated in FIGS. 3 a  to  3   g  is of the same basic design as the brush head  14  shown in FIGS. 2 a - 2   e . However, the tunnels  20  widen in a trumpet-like manner toward the border of the brush head  14  (FIG. 3 a ). The regions  22  of the bristle carrier  16 , which bound the tunnels  20  on the bristle-carrying side of the toothbrush  10  (FIGS. 3 c ,  3   f ,  3   g ), are likewise thin and of slightly curved design, with the result that toward the bristle-carrying side, together with the borders of the segments  17  of the bristle carrier  16 , they too form hollowed channels running transversely over the brush head  14  (FIG. 3 a ). Since the tunnels  20  widen in a trumpet-like manner toward the border of the brush head  14 , the channels on the bristle-carrying side of the brush head  14 , which are formed by the regions  22 , also appear in plan view in a form in which they widen in a trumpet-like manner toward the border of the brush head  14  (FIG. 3 a ). Just like the regions  22  of the bristle carrier  16  in the embodiment described in FIGS. 2 a  to  2   e , it is also the case here that the regions  22  of the bristle carrier  16  increase flexibility and act as a bending-limiting means. 
     The central segment  17  and the segment  17 ″ of the bristle carrier  16 , the segment  17 ″ being located opposite the brush handle  12 , are subdivided in this embodiment into two parts  17   a ,  17   b  by an interspace  34  which extends over the entire width of the brush head  14  (FIGS. 3 c ,  3   e ). This interspace  34  connects the tunnels  20  to one another and is likewise filled with the second, soft, elastic plastic (FIG. 3 d ). The interspace  34  with its soft, rubber-elastic filling makes it possible for the segments  17  of the bristle carrier  16  to be tilted along, and transversely with respect to, the longitudinal axis  24  of the brush head  14 . 
     A small web  36  at that end of the brush head  14  which is located opposite the brush handle  12 , said web connecting the bristle-carrying part  17 ″ a  to the part  17 ″ b  of the segment  17 ″, said part  17 ″ b  being located opposite the bristle-carrying part, prevents the two parts  17 ″ a  and  17 ″ b  of the segment  17 ″ from spreading apart during use and prevents the join between these parts  17″   a ,  17 ″ b  and the soft, elastic plastic in the interspace  34  from being released (FIG. 3 c ). The segment  17 ′ of the bristle carrier  16 , being located at the other end of the brush head  14  and being adjacent to the brush handle  12 , is not separated by the interspace  34 . Said segment merges into the brush handle  12  (FIG. 3 c ), which is produced from the same hard, elastic plastic as the bristle carrier  16 . 
     The basic design of the brush head  14  shown in FIGS. 4 a  to  4   g  is the same as that of the brush head  14  illustrated in FIGS. 1 a  to  1   g . The two have a bristle carrier  16  which is subdivided into five segments  17  by tunnels  20  and is made of hard, elastic plastic. 
     The difference between the embodiment shown in FIGS. 1 a  to  1   g  and the embodiment shown in FIGS. 4 a  to  4   g  is that in that embodiment of the brush head  14  which is outlined in FIGS. 4 a  to  4   g  the bristle carrier  16  has a groove  28  instead of a lateral groove  30 , this groove  28  extending, along the center longitudinal axis  24 ′, on the rear side, which is located opposite the bristle-carrying side, of the brush head  14  (FIG. 4 c ). The groove  28 , which is filled with the second, soft, rubber-elastic plastic, passes through the bristle carrier  16  such that the tunnels  20  are connected to one another via the groove  28  (FIGS. 4 c ,  4   d ,  4   f ,  4   g ). 
     For cost-effective production by two-component injection molding, the brush handle  12  has on the rear side, which is located opposite the bristle-carrying side, of the toothbrush  10  a handle groove  26  which, in the region of the brush head  14 , merges into the groove  28  along the center longitudinal axis  24 ′ of the brush head  14 . Both grooves  26  and  28  are filled with the soft, rubber-elastic plastic (FIGS. 4 c ,  4   d ,  4   e ). 
     The possible variations of the brush head  14  according to the invention are by no means covered in full by the embodiments described and illustrated in the figures. As is also made clear, in particular, by the exemplary embodiments shown in FIGS. 2 a  to  2   e  and  3   a  to  3   g , the geometrical configuration of the bristle carrier  16 , as seen in plan view, may be virtually of any desired shape. It is thus not necessary for the bristle carriers  16  and their segments  17  to be of rectangular design, as is illustrated in the examples of FIGS. 1 a  to  1   g  and  4   a  to  4   g . The same also applies for the tunnels  20  between the segments  17  of the bristle carriers  16 , as is illustrated in FIGS. 3 a ,  3   c ,  3   f . Variations in the outwardly visible distribution between parts made of the first, hard, elastic plastic and the second, soft, rubber-elastic plastic for design reasons are, of course, likewise conceivable. 
     In all the exemplary embodiments shown, the tunnels  20  extend over the entire width of the bristle carrier  16  and run continuously from side border to side border. It is, then, also conceivable for the tunnels  20  to be of non-continuous configuration, i.e. for the tunnels  20  to be interrupted by an intermediate element. 
     It is also possible to dispense with the tunnels  20  being filled with the second, soft, elastic plastic. In such an embodiment, the lateral groove  30  and/or the groove  28  and the handle groove  26  can be omitted. As a result, the brush handle  12  and the bristle carrier  16 , subdivided into segments  17  by the tunnels  20 , of such an embodiment consist just of a single material, that is to say the first, hard, elastic plastic. 
     It is possible for the brush head  14  designed according to the invention to be used not just for a manual toothbrush, as shown, but also for plug-on toothbrushes, as are used for electric toothbrushes. In the case of such a plug-on toothbrush, the brush head  14  according to the invention is connected to a plug-on part. 
     Instead of the brush head  14  being designed integrally with the brush handle  12  or the plug-on part, it is also possible for the brush head  14  to be connected to the brush handle  12  or the plug-on part in an exchangeable manner. 
     The configuration of the bristles or bristle clusters  18  may likewise be varied, as has already been indicated in FIG. 3 b  by the different lengths of the bristle clusters  18  and the brushing surfaces, some of which are cut obliquely. As has been mentioned, it is also possible for crosswise bristles or bristle clusters  18  which are positioned obliquely with respect to one another, as is illustrated in FIGS. 2 b  and  2   d , to be expedient and additionally to aid better cleaning of the teeth as a whole. 
     It is also possible for those regions  22  of the bristle carriers  16  which bound the tunnels  20  to be of different configurations. As described for the embodiments shown in FIGS. 2 a - 2   e  and  3   a - 3   g , the flexibility of the brush head  14  can be increased if the regions  22  of the bristle carriers  16  are thin and of slightly curved configuration. However, the capacity for expansion of these regions  22  in the longitudinal direction of the brush head  14  may also be improved, for example, by the regions  22  being thinned out toward their center. A very expansible, and thus very advantageous, form of these regions  22  is achieved by a thin configuration which is folded in the manner of an accordion in the longitudinal direction of the brush head  14 . This accordion-like construction is seen in FIG. 6 wherein the brush head has two side-to-side transverse tunnels similar to those in FIGS. 2 d  or  2   e , but wherein the thin connecting webs at the top and bottom of the tunnels at  22  and  22 ′ are formed as longitudinally extending zigzag pleats to facilitate brush head flexibility. This also applies correspondingly for the regions  22 ′ on the rear side, which is located opposite the bristle-carrying side, of the bristle carrier  16 , said regions  22 ′ being compressed elastically when the bristle-carrier segments  17  are deflected by force being applied to the bristle clusters  18 . 
     A configuration of these regions  22  of the bristle carrier  16  such as that illustrated in FIGS. 5 a  and  5   b  also results in very high flexibility of the brush head. FIGS. 5 a  and  5   b  show a toothbrush  10  which has a brush head  14  and is constructed analogously to the embodiment shown in FIGS. 2 a  to  2   e . However, of the thin regions  22  and  22 ′, which cover over the tunnels  20 , in the embodiment shown here the regions  22  on the bristle-carrying side of the brush head  14  are subdivided into two sections  22   a  and  22   b  by a parting plane  21  extending over the entire width of the brush head  14 , said two sections being in closing contact in the normal state, as shown in FIG. 5 a . Under bending stress, the parting plane  21  widens to form a gap  21 ′, as is illustrated in FIG. 5 b , which permits a large degree of bending. The restoring force of the soft, elastic plastic material in the tunnels  20  ensures that, as the bending stress decreases, the gap  21 ′ closes again to the full extent and the sections  22   a  and  22   b  of the regions  22  butt against one another again with closing contact. It is also the case in terms of torsional stress along the longitudinal axis  24 ′ of the bristle carrier  16  that the parting plane  21  in the regions  22  increases the flexibility of the brush head  14 .