Abstract:
A brush and in particular a tooth brush comprises a brush body and a bristle carrier supporting a plurality of bristles and being preferably removably retained on the brush body. The bristle carrier, consisting of soft-elastic plastic material, is formed as a cap and can be drawn over a projection of the brush body.

Description:
BACKGROUND OF THE INVENTION 
   The invention concerns a brush, in particular a tooth brush, comprising a brush body and a bristle carrier supporting a plurality of bristles and being preferably removably retained on the brush body. 
   The invention is described below, by way of example, as a tooth brush, however, it can be used in the same fashion with other cleaning and application devices having bristles, in particular, washing brushes, scrubbing brushes, cleaning brushes, toilet brushes, brooms, paint brushes, application brushes for creams, powder, cosmetics, medication, spices or paint or even floor treatment brushes, wherein these applications are explicitly included in the invention. 
   A manual tooth brush of conventional construction comprises a longitudinal brush body made in general of plastic material, whose rear section serves as a handle, and the front head end of which comprises a bristle field having a plurality of bristles fixed to the brush body. An electrically driven tooth brush has essentially similar construction, wherein the brush body is subdivided into a base part accommodating the driving motor and serving as handle, and an attachment part supporting, at its front head, the bristle field and comprising a transmission for converting the motion of an output shaft of the driving motor into an oscillating or back and forth rotating motion of the bristle field. 
   The bristle field of a tooth brush experiences the largest amount of wear through use. Since worn or bent bristles insufficiently clean the teeth and damage the gums, it is recommended to replace tooth brushes every three months. With conventional tooth brushes of this type, with the bristle field being rigidly connected to the brush body, the bristle body of manual tooth brushes must be entirely replaced when the bristles are worn and the attachment part of electric tooth brushes, including transmission, must be replaced. It has been realized for some time that this procedure is both uneconomical and ecologically questionable. 
   To prevent these problems, so-called removable head tooth brushes have been developed, wherein the bristle field seats on a removable bristle carrier, in particular in the form of a stable plastic plate which engages in a depression in the head of the brush body, limited by a projecting edge. Since the dimensions of the tooth brush head are limited for handling and application reasons, the edge of the depression reduces the bristle field size. This limitation is acceptable with manual tooth brushes. However, with electric tooth brushes whose bristle field is in any event smaller than that of manual tooth brushes for structural reasons, the bristle field becomes very small which consequently reduces the cleaning effect of the tooth brush. 
   Moreover, it has been shown that dirt and bacteria can accumulate in the depression and in the gaps between the brush body and the bristle carrier which are difficult to remove such that use of some tooth brushes with removable head is questionable with respect to hygiene. 
   To securely retain the removable bristle head on the brush body, same has to be sufficiently stable and thus hard which creates the problem that the sensitive mucous membranes come in contact with relatively hard structural parts when using the tooth brush. This could cause injuries. 
   In conventional tooth brushes, the bristles are usually rigidly held in the bristle carrier. This has the disadvantage that the bristles cannot deflect in the axial direction during cleaning and can deflect in a transverse direction only due to their intrinsic flexibility. When applying large cleaning forces, these forces transferred to the teeth and gums essentially without resilient absorption thereby possibly causing injuries. It has been attempted to dispose the bristle bundles in a resilient fashion on the brush support. However, the construction required therefor is very demanding and requires very expensive production methods. 
   It is the underlying purpose of the invention to produce a brush of the mentioned type which avoids the above-mentioned problems and which is of simple construction. 
   SUMMARY OF THE INVENTION 
   This object is achieved in accordance with the invention in a brush of the mentioned type in that the bristle carrier, consisting of soft-elastic plastic material, is formed like a cap and can be drawn over a projection of the brush body. 
   In accordance with the invention, the bristle carrier bearing the bristle field is formed as a flexible cap e.g. of an elastomeric plastic material which can be drawn, like a cover, onto a projection, in particular, on the brush body head such that it surrounds and covers the projection and is securely held on the projection by tensioning forces resulting in particular from the elastic deformation of the cap, however, can be removed from same when required. The tensioning or retaining forces of the cap-like bristle carrier are thereby determined by its ability to deform which depends on its geometric design, its wall thickness and the elastic properties of its material. 
   The inventive cap-like bristle carrier is drawn over the projection and in particular the head of the brush support and is not inserted therein, which has the essential advantage that the surface of the bristle carrier is larger than the surface of the projection overlapping it, such that the bristle field can be relatively large. 
   The soft-elastic and thus very flexible plastic material of the cap-like bristle carrier can be easily deformed in all directions such that the bristles can resiliently deflect in their axial direction and also perpendicular thereto when cleaning forces are applied. 
   The cap-like bristle carrier is held on the projection of the brush body by tensioning forces resulting from its elastic deformation thereby preventing formation of gaps between the bristle carrier and the brush body and accumulation of dirt and resulting formation of bacteria. 
   The cap-like bristle carrier covering the projection of the brush body serves at the same time as mucous membrane protection due to its soft-elastic material and has the further advantage that the constructional height of the brush is small. 
   A preferred embodiment of the invention provides that the bristle carrier comprises an upper, preferably diaphragm-like covering part having bristles on its upper side and supporting, on its lower side facing away from the bristles, a preferably continuous and peripheral flexible projecting edge or bridge mounted onto the covering part or formed in one piece therewith. The height of the bridge may be constant or also vary along the circumference. In the mounted state of the cap-like bristle carrier, the projection of the brush body is disposed below the covering part and between the peripheral bridge which is tensioned on the projection from the outside. Alternatively or additionally, a bridge may be provided which abuts from the inside on a recess wall in the brush body. 
   The bristles are disposed at least in partial areas of the upper side of the covering part whose whole surface is preferably provided with bristles. Additionally or alternatively, the bristles may be disposed at least in partial areas of the outer side of the bridge tensioned against the projection from the outside. 
   In a possible embodiment, the covering part of the cap-like bristle carrier may extend essentially level. The covering part may also have a spatial structure, at least in the mounted state. This can be achieved by providing the upper side of the projection of the brush body with a structured surface and disposing the flexible covering part of the bristle carrier onto the structured upper side of the projection such that it abuts and follows said structure. Therein, the spatial course of the covering part in the mounted state is determined by the surface structure of the projection of the brush body. Alternatively, it is also possible to provide the covering part itself with a structured surface which can be effected either during the production process, e.g. during injection-molding or injection of the bristles or by subsequent deformation, in particular compressing or deep-drawing of the initially flat covering part. 
   All embodiments may additionally be provided with bristles having differing bristle lengths and/or bristle orientations forming a topographic structure with different heights. 
   A further preferred design of the inventive brush provides at least one cavity below and/or within the cap-like bristle carrier. This cavity can provide the covering part supporting the bristles with elastic resilience, wherein the resilience is determined by the shape of the cavity and can be adjusted as desired by a damping fluid to be filled into the cavity. Alternatively, the cavity can be used to accommodate a medium to be applied during use of the brush. The medium may either be fluid or powdery cosmetics, tooth care products etc. Supply and application of the medium can be effected e.g. through openings in the flexible cap-like bristle carrier, hollow bristles or bristle bundles or through the capillary effect of bristle bundles. 
   In a simple embodiment of the cavity, the cap-like bristle carrier can be disposed onto the projection in such a fashion that an intermediate space forming said cavity is generated between the lower side of the covering part of the bristle carrier and the upper side of the projection such that the cavity is limited by the bristle carrier and the brush body. 
   A preferred further development of the invention provides that a dividing wall divides the cavity into separate chambers which preferably contain media having different characteristics which are mixed and react with one another, optionally, not before leaving the respective chamber. Moreover, the cavity may contain an agent which reacts with an externally applied tooth paste or cleaning cream thereby forming an optimized agent for the intended purpose. 
   The amount of the medium leaving the cavity or the chambers depends on the deformation of the cavity and in particular of the covering part limiting same. 
   The cavity or the chambers may be provided with a foamed insert which is inserted either as separate pre-fabricated part or injection-molded in a multiple-component injection-molding process during production of the cap-like bristle carrier or introduced by foam mold. The foamed insert serves as a damping member for deformation of the covering part supporting the bristles. Moreover, the insert may also be soaked with a medium to be applied. The use of hydrophilic foam allows storage of liquid or gaseous media, contained by said foam, in the cavity. Such enriched foams are easy to handle and, in particular, can be exchanged. 
   The cavity can be associated with a storage region connected therewith containing a medium to be applied which is supplied, through a passage, to the cavity containing a foamed or sponge insert for throttled and uniformly dosed supply of the medium to the bristle field. 
   The design of a cavity can also be effected or improved when at least sections of the brush body are formed as cups and the cap-like bristle carrier traverses the cup-like area like a cover. If the brush body as a whole is formed like a cup and is traversed and covered by the cap-like bristle carrier, formation of a very flat brush with an inner cavity is possible which can be filled with a medium to be applied or also charged with cartridges, tablets, filled foamed or sponge inserts. 
   The resilience of the bristle field is determined essentially by the thickness of the diaphragm-like covering part. The deformation possibilities increase with reduced thickness of the covering part. With electrically operated tooth brushes, a covering part thickness in the range between 0.5 and 3.0 mm has been shown to be reasonable. This has the essential advantage that the overall height of the brush is very low. Deformation of the cap-like bristle carrier and in particular of the covering part can be further adjusted by forming projections and/or recesses on the inner side of the bristle carrier and in particular of the covering part. The projections form reinforcements which impair deformation whereas the recesses define areas which are particularly soft for deformation. 
   To prevent excessive deformation of the bristle carrier during use and also guarantee that the bristle carrier returns into its initial position without load, the inner side of the bristle carrier may be provided with at least one spring element supported on the brush body. During use, the covering part is deformed against the resilient force of the spring element which, when unloaded, returns the covering part into its initial position. The spring element may preferably be formed by a shackle or bridge fashioned on the lower side of the covering part. 
   In order to be able to also properly clean inclined surfaces, tilting of the bristle field relative to the brush body is advantageously possible. This can be easily achieved when the bridge is flexible in an axial direction i.e. essentially perpendicular to the covering part and the bristle field. Since the specific elasticity of the bridge is limited, the axial flexibility of the bridge can be assisted when at least sections thereof are formed as bellows. 
   The bridge, extending on the outside of the projection of the brush body, moreover serves as a protective coating and in particular as mucous membrane protection for the user. Elements may be additionally integrated in the bridge which provide impact protection and which resiliently yield with contact. This can be achieved e.g. in that the bridge comprises elastically deformable projections on its outer peripheral surface which may have the shape of a ring, a loop or a punched tape. 
   A possible embodiment may provide that the bridge extends in the edge area of the covering part. In an alternative, the covering part may project laterally i.e. radially beyond the bridge thereby forming a freely protruding edge projection. These freely protruding edge sections may be particularly flexible and thus contribute to protective mucous membrane massage. If, during use, a correspondingly equipped brush meets an inclined surface area, the edge section bends relative to the covering part such that the inclined surface area is cleaned simultaneously on both abutting surfaces. 
   Normally, the tensioning and frictional forces resulting from elastic deformation of the cap-like bristle carrier are sufficient for retaining same securely on the projection of the brush body. It is possible to provide special engagement means for fixing the bristle carrier on the brush body in a non-rotatable fashion. Special engagement means may also be provided to which the bristle carrier is fixed on the brush body in a non-rotatable fashion in the form of e.g. sealing projections provided on the inside of the bridge which engage in corresponding recesses of the brush body thereby providing fixation in a non-rotatable and/or non-lifting fashion. Alternatively, the sealing projections may also be formed on the brush body and the recesses may be formed on the bridge. 
   The dimensions of the cap-like bristle carrier are adjusted to the respective application. A relatively flat cap may be provided having a covering part with short bridges. However, it is also possible to design the cap-like bristle carrier like a stocking, i.e. for forming a longitudinal cylinder with relatively long bridges as is e.g. required for forming an interdental brush or individual rotating bristle bundles. 
   The bristles may be pre-fabricated and mounted to the bristle carrier in a conventional fashion. Alternatively, it is also possible to form the bristles in one piece with the bristle carrier and in particular to injection-mold them together using a one-component or two-component method. It is possible to form bristles of different shape, different materials and different orientation on the bristle carrier. 
   When the cap-like bristle carrier has a cavity, the pressure increase occurring during deformation of the flexible bristle carrier in the cavity can be utilized for actuating an indicator element. The indicator element can e.g. be a displaceably disposed piston which is pushed outwardly when the cavity increases and is retracted into its initial position when the deformed bristle carrier is returned, thereby producing an indication of the pressing force which the user applies to the bristles. Alternatively or additionally, the medium contained in the cavity could change color under pressure to thereby also represent a pressure indication. 
   The pressure increase in the cavity may also open an outlet valve for a medium to be applied which is contained in the cavity, thereby ensuring that the medium can exit the cavity only upon application of a corresponding pressure by the user. 
   Deformation of the flexible bristle carrier can be used directly for adjusting an actuating element in that the displacement of partial areas of the wall of the cap-like bristle carrier occurring during deformation is converted directly into adjustment of a mechanical indicator. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
     Further details and features of the invention can be extracted from the following description of embodiments with reference to the drawing. 
       FIG. 1  shows a representation of the front end of a tooth brush with attached cap-like bristle carrier; 
       FIG. 2  shows a sectional view of a bristle carrier; 
       FIG. 3  shows a sectional view of an alternative embodiment of a brush with attached bristle carrier; 
       FIG. 4  shows a modification of the embodiment in accordance with  FIG. 3 ; 
       FIG. 5  shows a sectional view of a further alternative embodiment of a brush with attached bristle carrier; 
       FIG. 6  shows a modification of the embodiment in accordance with  FIG. 5 ; 
       FIG. 7  shows a modification of the embodiment in accordance with  FIG. 6 ; 
       FIG. 8  shows a modification of the bristle carrier in accordance with  FIG. 2 ; 
       FIG. 9  shows a sectional view of a bristle carrier with a modified geometrical shape; 
       FIG. 10  shows a sectional view of the bristle carrier with reinforcement; 
       FIG. 11  shows a sectional view of a bristle carrier with a recess; 
       FIG. 12  shows a sectional view of a bristle carrier with spring element; 
       FIG. 13  shows a sectional view of a bristle carrier with an alternative spring element; 
       FIG. 14  shows a sectional view of a bristle carrier with a deformable bridge; 
       FIG. 15  shows a sectional view of a bristle carrier with lateral protection elements; 
       FIG. 16  shows a view from below of the bristle carrier in accordance with  FIG. 15 ; 
       FIG. 17  shows a further alternative embodiment of the bristle carrier in accordance with  FIG. 2 ; 
       FIG. 18  shows a modification of the bristle carrier in accordance with  FIG. 17 ; 
       FIG. 19  shows a further alternative embodiment of the bristle carrier in accordance with  FIG. 2 ; 
       FIG. 20  shows a modification of the bristle carrier in accordance with  FIG. 19 ; 
       FIG. 21  shows a view from below of a bristle carrier with non-rotational fixation; 
       FIG. 22  shows a view from below of a bristle carrier with alternative embodiment of the non-rotating fixation; 
       FIG. 23  shows a sectional view of a stocking-shaped bristle carrier; 
       FIG. 24  shows a sectional view of a bristle carrier with engagement fixation; 
       FIG. 25  shows a sectional view of an alternative of a bristle carrier with engagement fixation; 
       FIG. 26  shows a bristle carrier on a plate-shaped projection; 
       FIG. 27  shows a sectional view of a bristle carrier of several components; 
       FIG. 28  shows a sectional view of a bristle carrier of several structural parts; 
       FIG. 29  shows a sectional view of a brush with cap-shaped bristle body; 
       FIG. 30  shows a sectional view of a bristle carrier with cavity; 
       FIG. 31  shows a sectional view of a bristle carrier with cavity and storage region; 
       FIG. 32  shows a horizontal section through a bristle carrier comprising a multiple chamber cavity; 
       FIG. 33  shows a sectional view of a bristle carrier with injection-molded bristles; 
       FIG. 34  shows a sectional representation of a bristle carrier with indicator element; 
       FIG. 35  shows an alternative embodiment of the bristle carrier in accordance with  FIG. 34 ; 
       FIG. 36   a  shows a sectional representation of a bristle support with alternative indicator element in a first functional state; 
       FIG. 36   b  shows a sectional representation of a bristle support with alternative indicator element in a second functional state; 
       FIG. 37   a  shows a sectional representation of a bristle support with alternative indicator element in a first functional state; 
       FIG. 37   b  shows a sectional representation of a bristle support with alternative indicator element in a second functional state; 
       FIG. 38   a  shows a sectional representation of a bristle support with alternative indicator element in a first functional state; 
       FIG. 38   b  shows a sectional representation of a bristle support with alternative indicator element in a second functional state; 
       FIG. 39   a  shows a sectional representation of a bristle support with alternative indicator element in a first functional state; 
       FIG. 39   b  shows a sectional representation of a bristle support with alternative indicator element in a second functional state; 
       FIG. 40  shows a sectional view of a brush body with two attached bristle carriers; 
       FIG. 41  shows a further development of the embodiment of  FIG. 40 ; 
       FIG. 42   a  shows a sectional representation of a bristle support with a valve in a first functional state; and 
       FIG. 42   b  shows a sectional representation of a bristle support with a valve in a second functional state. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1  shows the front part of a tooth brush  10  with a brush body  11  serving as handle comprising, at its front end, a block-like projection  11   a  serving as support. A flexible cap-like bristle carrier  13  is drawn over the projection  11   a  and supports a plurality of bristles  12  on its upper side.  FIG. 2  shows that the bristle carrier  13  comprises a flat diaphragm-like covering part  13   a  which supports the bristles  12  on its upper side and comprises, in the edge area on its lower side facing away from the bristles  12 , a peripheral bridge  13   b  projecting downwardly. The inner dimensions of the bristle carrier  13  are somewhat smaller than the outer dimensions of the projection  11   a  such that it can be attached to the projection  11   a  under elastic deformation without play. Due to the elastic deformation, the peripheral bridge  13   b  of the bristle carrier  13  stretches over the projection  11   a  from the outside and is securely held thereon. 
   The bristles  12  may extend parallel or at an angle to one another, wherein in the latter case, they project laterally over the bristle carrier thereby increasing the work surface. Alternatively, it is also possible to bend the bristles individually and/or orient them in different directions or crosswise. 
   While the projection  11   a  represented in  FIG. 1  comprises an essentially horizontal surface on which the covering part  13   a  of the bristle carrier  13  is level, in  FIG. 3  the surface of the projection  11   a  is convex which gives the covering part  13   a  of the drawn-over bristle carrier  13  a likewise convex shape. 
   In accordance with the embodiment of  FIG. 4 , the covering part  13   a  also follows the surface structure of the projection ha which is wavy in the present case. 
   In accordance with  FIG. 5 , the covering part  13   a  of the bristle carrier  13  has a convex shape and is disposed at a separation from the surface of the projection  11   a  thereby forming a cavity  14  between the bristle carrier  13  and the projection  11 . Upon exertion of external pressure onto the bristles  12 , the bristle carrier  13  may resiliently yield towards the inside, whereby the fluid contained in the cavity  14 , e.g. air, damps deformation of the bristle carrier  13 . In a further development in accordance with  FIG. 6 , a foamed body  15  can be introduced into the cavity  14  whose specific elasticity damps deformation of the bristle carrier  13 . The foamed body  15  may be filled with a liquid or gaseous medium to be applied, wherein the medium may exit through passages  16  ( FIG. 7 ) formed in the covering part  13   a  of the bristle carrier  13 . 
   In the previous embodiments, the bristle carrier  13  is provided with bristles on the upper side of the covering part  13   a  only.  FIG. 8  shows an embodiment wherein the outer surface of the bridge  13   b  has also bristles  12 . Therein, the bridge  13   b  for forming a longitudinal stocking-shaped hollow body may be relatively long ( FIG. 9 ). 
   The bristles  12  may be disposed over the entire surface of the outer side of the bristle carrier  13  or only on partial areas thereof. Moreover, the bristles may have identical or different lengths and form, with their tip sections, a covering surface of any topographic shape. 
   In the embodiment of the bristle carrier  13  shown in  FIG. 10 , a projection  18  serving as reinforcement is formed on the lower side of the covering part  13   a  by means of which the deformation characteristics of the covering part  13   a  change with external load and can be adjusted to the desired application. While the projection  18  increases the rigidity of the covering part  13   a , the covering part  13   a  may also alternatively comprise recesses  19  which reduce the rigidity of the covering part ( FIG. 11 ). 
   In accordance with  FIGS. 12 and 13 , spring elements  20  are provided or formed on the lower side of the covering part  13   a  which are supported on the upper side of the projection  11   a . The spring elements  20  are compressed during external loading of the covering part  13   a  and guarantee that the covering part is forced back into its initial position after de-loading. In accordance with  FIG. 12 , the spring element  20  is formed by a strap-like shackle held at both ends on the covering part  13   a . In  FIG. 13 , a double S-shaped support is provided as spring element which is mounted on its upper end to the covering part  13  and is supported with its lower end on the projection  11   a.    
   In accordance with  FIG. 14 , the bridge  13   b  of the bristle carrier  13  is formed sectionally as bellows  21  thereby enabling tilting of the covering part  13   a , having the bristles  12 , relative to the projection  11   a  during use without the danger that the bristle carrier  13  slides off from the projection  11   a . This provides good, resilient support of the bristles, even on an inclined cleaning surface. 
   The bridge  13   b  abutting the side surface of the projection  11  in the mounted state also serves as a protective coating and, in particular in a tooth brush, as mucous membrane protection.  FIGS. 15 and 16  additionally provide that the bridge  13   b  comprises, on its outer peripheral surface, elastically deformable projections  22  which are formed by sectionally wavy configuration of the bridge  13   b  in accordance with  FIG. 16 . 
     FIGS. 17 and 18  show two embodiments wherein the covering part  13   a  projects laterally or radially outwardly over the bridge  13   b  thereby forming a freely protruding edge section  13   c . In this fashion, the work surface provided with bristles  12  is increased and, due to the flexibility of the freely protruding edge section  13   c , they can easily abut on and clean a curved or angled surface.  FIG. 18  shows a further development, wherein the outer sections of the freely protruding edge sections  13   c  are bent downwardly thereby forming an outwardly curved, convex section. 
   The deformability of the bristle carrier  13  is determined i.a. by its geometric design. To provide the peripheral bridge  13   b , which essentially has a holding function, with sufficient stability and to simultaneously allow easy deformation of the covering part  13   a , these two sections may have different wall thicknesses, as shown in  FIG. 19 . Therein, the slightly stronger bridge  13   b  continuously passes over into the relatively thin covering part  13   a . To prevent excessive deformation in the central region of the covering part  13   a , this area may have a larger wall thickness, e.g. a reinforcement  18  as represented in  FIG. 20 . 
   To retain the bristle carrier  13  on the projection  11   a  in a non-rotatable fashion, the inner side of the bridge  13   b  is provided with a single recess  30  (shown in  FIG. 21 ), which can engage with a correspondingly formed nose (not shown) of the projection  11   a . Alternatively and in accordance with  FIG. 22 , the inner peripheral surface of the bridge  13   b  may be polygonal and, in particular, in accordance with the figure, octagonal and disposed on a corresponding polygonal projection. 
     FIG. 23  shows the bristle carrier  13  as a longitudinal stocking-shaped cylinder with a relatively small covering part  13   b  supporting bristles on its upper side configured in the shape of a triangle. Such a bristle carrier may be used as a bristled cap for interdental brushes or as a removable cap for electric tooth brushes having individual rotating bristle bundles. 
   To secure the cap-shaped bristle carrier  13  on the projection  11   a , the inner side of the bridge  13   b , in the embodiment in accordance with  FIG. 24 , comprises a peripheral inward facing engagement nose  23  which can engage in a correspondingly formed recess of the projection  11   a . In accordance with  FIG. 25 , the upper section  11   a   1  of the projection  11   a  is bulged to the outside and is undercut by the bridge  13   b  of the flexible bristle carrier  13 . In a further embodiment in accordance with  FIG. 26 , the projection  11   a  is formed as a plate and is undercut by the bridge  13   b  of the attached cap-like bristle carrier  13 . 
   The bristle carrier  13  can be made from one single material. However,  FIGS. 27 and 28  show that the covering part  13   a  and the bridge  13   b  can be produced from different flexible plastic materials, in particular via a two-component injection-molding process. In this fashion, the material properties of the individual areas can be well adapted to their required function during use. Alternatively ( FIG. 28 ), the covering part  13   a  and the bridge  13   b  may be pre-fabricated and connected to one another later by welding, gluing, clamping or in any other manner. 
   As mentioned above, a cavity  14  may be formed between the projection  11   a  of the brush body  11  and the cap-like bristle carrier  13 . Formation of the cavity  14  is facilitated when sections of the projection  11   a  of the brush body  11  are cap-shaped or when it is entirely formed like a cap, as shown in  FIG. 29 . A foamed insert is thereby inserted in the cavity  14 . 
     FIG. 30  shows an embodiment wherein a further dividing wall  13   d  extends between the inner wall of the bridge  13   b  of the bristle carrier  13  below the covering part  13   a  such that the cavity  14  is formed within the bristle carrier  13  between the upper covering part  13   a  and the lower dividing wall  13   d . The further development shown in  FIG. 31  is provided with a storage region  25  for a medium to be applied which is located below the cavity  14  in which a foamed insert  24  is disposed. The cavity  14  is separated from the storage region  25  by a dividing wall  31  provided with passages  26 . The medium may flow from the storage region  25  through the passages  26  into the foamed insert  24  of the cavity  14  and is delivered therefrom to the bristles  12  via passages  16  in the upper covering part  13   a.    
   As shown in  FIG. 32 , the cavity  14  may be subdivided by inner dividing walls  32  into several separate chambers  14   a ,  14   b ,  14   c  which can accommodate various media which flow together and react following exit. 
     FIG. 33  shows an embodiment. The bristles are not pre-fabricated by a spinning method and then mounted to the bristle carrier, rather are produced in one piece therewith using a one-or two-component injection-molding process. 
     FIGS. 34 to 39   b  show various embodiments wherein the load-related pressure increase in the cavity  14  occurring during deformation of the bristle carrier  13  is indicated by an indicator. In accordance with  FIG. 34  a displaceable piston  27  is disposed in a connection piece-shaped section  13   e  of the bridge  13   b  of the bristle carrier  13 . When the user presses from the outside on the bristles  12  or the covering part  13   a  (arrow D), the volume of the cavity  14  is reduced and the inner pressure increases thereby pushing the piston  27  outwardly as indicated by arrow S in  FIG. 34 . The user can observe the pushed-out piston. The degree of displacement of the piston  27  indicates the inner pressure of the cavity  14  and thus the external pressure applied by the user. The displacement of the piston  27  can also serve for triggering further mechanical, acoustical and/or electrical signals. 
   In accordance with  FIG. 35 , a support acting as spring  20  is formed on the lower side of the covering part  13   a  and is supported on the upper side of the projection  11   a . Also in this case, a piston  27  is displaceably disposed in a passage of the bridge  13   b  which abuts with its inner end on the spring  20 . If the user presses from the outside onto the bristles  12  or the covering part  13   a  (arrow D), the spring  20  is laterally deflected thereby outwardly displacing the piston  27 , as shown by arrow S. 
   In accordance with  FIG. 36   a , a thin-walled closing diaphragm  28  is formed on the outer side of a pipe socket-shaped passage  36  formed in the bridge  13   b  which, with increasing inner pressure, can be blown up like a balloon, as indicated in  FIG. 36   b , thereby providing an indication of the pressure applied by the user onto the bristles (arrow D). 
   In accordance with  FIGS. 37   a  and  37   b , a passage  37  is directly formed in the wall of the bridge  13   b  and sealed by a closing diaphragm  28  which can be expanded and—as shown in  FIG. 38   b —bulges outwardly with increased inner pressure in the cavity  14 . Therein, the closing diaphragm  28  may be pre-fabricated as a separate structural part and then mounted in the passage  37 . It is, however, also possible to injection-mold the closing diaphragm  28  on the bridge  13   b , in one piece. 
   A similar closing diaphragm  28  may be formed in a passage  34  of a lid  33  closing the lower side of the bristle carrier  13  ( FIG. 38   a ) which curves downwardly with increased inner pressure ( FIG. 38   b ). 
   In accordance with the embodiment of  FIGS. 39   a  and  39   b , an indicator bar  29  is displaceably guided in the lid  33  and is formed, at its upper end, on the covering part  13   a . When the covering part  13   a  is downwardly deformed by application of external pressure, the indictor bar  29  is pushed downwardly out of the lid  33  ( FIG. 39   b ) and can be directly used as a pressure indicator or, as described above, for triggering a corresponding signal. 
     FIG. 40  shows an embodiment with which one cap-like bristle carrier  13  is disposed on each of two different sides of a projection  11   a  of a brush body  11 . If the inner space of the projection  11   a  in accordance with  FIG. 41  is divided by a dividing wall  11   a   2  into two separate chambers, different media can be disposed therein to each be associated with one specific bristle carrier  13 , such that the user can select the one or other medium depending on the orientation of the brush. 
   In accordance with the embodiment shown in  FIGS. 42   a  and  42   b , a passage  16  is provided in the covering part  13   a  which can be closed or opened by means of an adjustable valve element  35 . The valve element  35  is disposed on the lower side of the covering part  13   a  via a strap formed thereon as a single piece and can be adjusted between the closing and opening position under elastic deformation of the strap  34 .