The present invention relates to a toothbrush having retactable and absorbed bristles.

Experts in the field are very familiar with toothbrushes which have adressed the problem of adapting the operation of brushing a complex and variable surface such as that of the teeth, with the traditional constitution of the toothbrush, that is, a handle for gripping and a head carrying the bristles specific for the cleansing operation.

In traditional toothbrushes, the head carrying the bristles has a base which clasps bristles, individually or in tufts, in such a way that the bristles- themselves remain either simply bound or housed and held at one end, while at the other end, in order to carry out the designated function, they are free and co-operative.

By examining the specific function of a toothbrush, it can be observed that from the rubbing action of the bristles upon the surface of the teeth, considering both the anterior faces of the teeth wich come in contact with the lips, and the vestibular faces of the teeth which cone in contact with the toungue, and considering that there exists an external surface, that is facing the walls of the mouth, and an internal surface, that is facing the palate, the cleansing action takes place in two phases: one of simply rubbing, another of rubbing and consequent removal of bacterialplaque and new formations of

tartar, the second removing those remainders of food which give rise to the formation of the above mentioned plaque and tartar.

Another observation that can be made is that the bristle must necessarily enter in contact with the gums, this is because the teeth are encapsuled in and surrounded by the gum, in a manner such that, when brushing the teeth, interferring with the gums can not be avoided. If we observe how the cleansing action takes place while contemporarily noticing the state of the art toothbrushes, we see that the rubbing and cleansing action is determined by the pressure with which the bristles come in contact with the teeth: that is, the more the user wishes to clean the teeth, the more pressure he applies through the handle or the grip of the toothbrush, said pressure is discharged upon the head and consequently upon the bristles.

A first point to take note of is that the bristles are naturally and in a variable measure, elastic; it is to this very elasticity, to put it in an elementary and primitive way, that is demanded the action of adaptation of the bristles to the surface of the teeth. That is, the degree of elasticity of the bristles reduces the pressure and the pushing of the head for the action of cleansing, upon the irregular surface of the teeth.

It should be noticed that the bristles are housed and bound on the head, in tufts, therefore the elasticity of each single bristle co-operates with a movement in different areas of retraction and relaxation, that is of variation of the cleansing

pressure.

If we observe the shape of the surface of the teeth and we furthermore consider that teeth are not always regular and perfectly aligned, or always whole and well modelled, we notice that the simple and natural retractability of the bristles due to the material of which they are made of does not allow an efficient rubbing and cleansing of the teeth themselves and of their interstitial spaces; it would be desirable that the degree of elasticity of the bristles be greater and, it could be said, that the' retractability be softened, so as to be able to apply manually or mechanically the desired form knowing that the same apply the abrasive or removing force only where it is needed, that is following the shape of the surface of the teeth and wedging itself in the interstitial spaces or in the small cavities or in the asperities.

Therefore, it is due to the above mentioned reasons that to the state of the art it has been throught to interpose at the base of the bristles' housing, means which allow the bending of the base itself in which the bristles or the tufts of bristles themselves are bound. The main and most relevant solution has been that of providing a resilient membrane upon which the bristles or tufts of bristles are abutted on the position of housing and of binding in the head of the toothbrush. The following patents are known: United States patents US 2.882,554 (HADIDIAN), and US 3.082.457

(LUCIBE LO), British patent GB 1.221.793 (WORKSHOP FOR THE BLIND), Danish patent DK 2.909.688 (WEBER), and French patent FR 8.405.896 (TARAVEL).

These proposed solutions are all based upon the fact that the bristles, individually or in tufts, when presented against the resilient membrane through bores in the head, obtain the purpose through two basic possibilities:

- a group of patents refers to the characteristic of deformability that the elastic membrane has because the membrane itself is in turn placed upon means which limit its possibility of deformation (for example United States patents US 2.882.554 HADIDIAN and US 3.082.457 LUCIBELLO); a second group (for example the British patent- GB 1.221.793 and French patent FR 8.405.896 TARAVEL), is based upon the presence, also on the housing and binding base of the bristles or tufts of bristles, of a elastic organ which carries out the action by virtue of its intrinsic characteristics, that is by a degree of deformability of the material of which said membrane is made of, and which gives place to an excursion of the bristles contained within a defined limit. Both solutions are derived from two assumed theories which use does not confirm: the philosophy according to which the membrane is presented against rigid means - grids, plates, etc., etc., to obtain the coercive limit of the bristles' retraction, does not take in account that the operator of the action of rubbing and cleansing cannot regulate the pressure

that he applies upon the head of the toothbrush through a controlling method. The more he presses the head of the toothbrush against the teeth, the more the bristles are first, deformed, that is they retract within the limit allowed by the elasticity of the material of which they are made, and subsequently, they retract within the limit allowed by the membrane's deformabilit , after which they penetrate into the zone of the membrane corresponding to the means for limiting the deformability.

This gives rise to requests which despite the elastic characteristics of the materials, cause the durability of the toothbrush to be limited, and progressively cause the bristles, as one of the ends of the same deteriorate the membrane, to lose efficiency of retractability.

The other basic theorical reasoning of those who retain that it should be the intrinsic characteristics of the material of which the membrane is made, that should allow a single elastically retractable organ which enables the bristles to retract, is disclaimed by the observation that the bending given by the elasticity of the continuous membrane, even when the bristles are united in tufts, occurs in extended areas, that is, almost with a "wave" of deformation; it can substantially be affirmed that the bristles retract following a sinusoidal curve and that therefore, by observing the morphology of the teeth it can be well understood that it cannot optimally carry out the actions of rubbing and cleansing.

The present invention is based upon from a completely different assumption: the action of retraction of the bristles must take place in limited groups of bristles, following a discontinuous line of deformability, and independently for each tuft, assuring, when providing for the mounting in tufts, a non-interference in the action of each tuft and a degree of operativity of the tuft directly derived from the surface in which each single tuft operates, since each tuft has individual means of deformation, capable of comfortably absorbing the bending and retraction desirable for the bristles.

The purpose of the present invention is to overcome the above described inconviniences and to obtain the above proposed advantages, through a toothbrush which groups the bristles in tufts and allows the action of the tufts to take place within a range of deformability given only by the shape of the area in which the head of the toothbrush operates. To achieve this purpose, this invention proposes a toothbrush provided with a handle or grip, a rigid brushing head, a number of bristles, of which one end is bound and another is free for carrying out the action of rubbing and cleansing of a highly variable and complex surface such as that of the teeth, characterized by comprising: a head, presenting a blind face having a function of supporting base and a superior body connected to said base by a perimetral relief, such as to form an elongated box-like element, in which are provided a number of bores which pass through the

superior face of the block consisting of the head along an axis orthogonal to the base and within said bores a plurality of tufts of bristles in a number exactly identical to that of the bores provided, are housed inside element forming the brushing head; the tufts of bristles passing through the superior face of the head, in order to slide up and down, are bound at the base in a capsule and thus prevented from exiting definitively along the orthogonally running axis with respect to the base itself; impact absorbing means for the sliding action of the tufts of bristles in the direction given by the passing through of the bores, one group independently from the other, elastically deformable, placed and bound within two grooves, one above and the other below, said impact absorbing means earring out a springing action, that is to receive the downcoming of the tufts of bristles through the bores, whenever the bristles meet with a prominence in the surface being brushed and return the said bristles upwards through the bores when the bristles meet with a subsidence in the brushed surface; this occurring at a parity of force applied upon the head; alternatively, the same purpose can be achieved through equivalent means, which however housed between the two grooves, work.ing as compression springs; binding means for the tufts of bristles and contemporarily containers in the head for the impact absorbing means for the tufts of bristles, consisting of a cilindrical capsule having an H-shaped section, which in its superior part houses the base of the

bristles gathered in tufts and in its inferior part are placed the impact absorbing means wich determine the sliding of the tufts in both upward and downward directions within predetermined limits. The present invention is herewith more thoroughly explained, in its preferred practical embodiment, stated for the purpose of examplif ing and not intending to limit the invention, with reference to the enclosed drawings, in which: - fig. 1 shows the head of a toothbrush according to the present invention, showing in cross section along median plane B B of figure 2;

- fig. 2 shows a cross section of the head of a toothbrush according to a perpendicular plane to the first, indicated by A A in fig. 1; fig. 3 shows a plan view of the head of a toothbrush according to the present invention; fig. 4 shows a partial section view of a part of a detail of figure 1, showing the tufts of bristles with the means which allow the absortion of impact; fig. 5 shows an axonometric view of a very enlarged part of a capsule with helicoidal elements constituting the impact absorbing means; - fig. 6 shows a section view of a very enlarged part of a tuft of bristles with its corresponding impact absorbing means; fig. 7 shows an axonometric view of an enlarged part of the capsule containing tufts of bristles; fig. 8 shows a variation of embodiment of a

toothbrush according to the present invention and shows a partial detailed section view of the head of a toothbrush showing the tufts of bristles with alternate means with respect to fig. 4, which allow the absorption of impact, based upon the same informing principles of the main embodiment.

In figures 1 to 6, the number 1 indicates the head of a toothbrush, integral with a handle for gripping 11 and presenting a blind face 2 as a supporting base and a superior body 3 which vertically surrounding the peripheral edges 13 and 23 forms an elongated box-like element. The supporting base 2, within a perimetral relief 21, contains element 3, 13, 23, which having a reversed U-shape constitutes the head of the toothbrush.

In superior body 3, are provided a number of bores 6, for example about thirty, of a diameter large enough to allow profitably the passage of the tufts of bristles 9, present in an number equal to that of the bores 6. The tufts of bristles 9, with respect to the bores 6, are by no means bound, and therefore can not only slide along them following the axis indicated with 14 and coincidental with the axis of the bores, but can carry out rotatory movements both in directions indicated by 16 and by 18, that is from right to left and from left to right. The vertical sliding described following axis 14 takes place in conjunction with rotational movements 16 and 18.

The tufts of bristles 9, have a free ending 10

and a bound ending 20; ending 10 represents the zone through which the bristles carry out the function of rubbing and cleansing the teeth; it also represents the point upon which is applied the force derived from the pressure with which, through the handle 11 the head is pressed against the teeth; the bound ending 20, is the zone where the tufts of bristles discharge the vertical force recieved along axis 14 and whereupon, when are not considered appropriate means for absorbing the impact of said force, that is that the base should have the sole function of containing the tufts - the bristles would curve themselves and deform diameter 15, until one tuft interferes with the other. The possibility given instead by the tufts being able to descend along axis 14 and each tuft being able to slide independently of the others, enables the single tufts to take on the most uneven postitions as, for example, in figure 4 in 25, 25a, 25b. As shown in figures 6 and 7, the tufts 9, are housed and bound in a cilindrical capsule 30 having an H-section, subdivided internally by a septum 31 into two hollow portions 32 and 34 each having an open entrance, the superior portion 32 towards the top 37 and the inferior portion 34 towards the bottom 37a.

Said cilindrical capsule 30, is provided in its inferior part with an anular protrusion 40, of a diameter larger than the capsule itself, placed at the base 33, from which depart ribbings in relief 38 and 38a which rising vertically along the entire height of the capsule from 33 to 35, have a helicoidal shape.

In the hollow portion 32, the tufts 9, gathered into a total diameter 17 corresponding to diameter 37 of capusle 30, are bound, by bind soldered or glued toghether, up to a height approximately corresponding to the hollow portion 32 itself, as delimited within capsule 30 by septum 31.

The hollow inferior part 34 of capsule 30, houses and binds the head of the impact absorbing means for the vertically sliding action of the tufts 9, said tufts being placed beggining at the intrados defined by septum 31 and with their base housed and bound in a groove 29 made in the extrados of blind face 2, consisting of the base of the head.

As shown in figures 4, 5, 6, in a variation of the embodiment, the impact absorbing means for the sliding movement of the tufts of bristles 9, contained by capsules 30, are consisting by protruding helicoidal elements 42, deriving as a whole piece from a capsule of defor able and reversible material, for example synthetic or natural elastomere, which through ribbings 43, 45, 47, 49, carry out the function of a sprining action, that is, they admit the dowmcoming, particularly towards blind face 2 of the base, of the tufts of bristles 9 through bores 6 when the tufts meet with a rise in the surface of the teeth during brushing and send the tufts of bristles 9 back up through the bores 6, when the they meet with a subsidence on the brushed surface.

As shown in figure 7, the caspule having elicoidal elements 42, has a square base 44, housed in a corresponding groove 29, and a cirular head 46,

housed in the inferior concave portion 34 of the tuft- carrying capsule 30.

Several variations are possible for providing the impact absortion of the sliding action of the tufts of bristles 9, gathered in capsule 30, equivalent to capules having helicoidal elements 42 above described based upon the principle of carrying out a springing action of compression and returning between two grooves 34 and 29. As shown in figure 8, for example, in a alternative embodiment, hollow portion 34 of capsule 30 carrying tufts of bristles 9, houses an impact recieiving helicoidal spring, bound at its head 146 in the intrados of the inferior hollow position 34 of capsule 30, and at the base 144 in groove 29 of the blind face 2 of the head of the toothbrush.

In head 1, between bores 6, through which slide capsules 30, carrying tufts of bristles 9, full interstitial zones 5 are provided; these allow each single tuft 9 to carry out the movement in a vertical direction, downwards and upwards, without interferring with the adjacent tuft.

In cylinders 24, which are formed in the head 1, through bores 6, the capsules 30, having a ring at the base 33 of the same diameter as the bores, descend and rotate from right to left forced into rotatory movement 16 by ribbings 38 and when returning the same ribbings constrain the said capsules into a rotatory movement from left to right in rotatory direction 18. As shown in figure 4, while capsules 30 carrying tufts 9 are completely outside head 1, in the

maximum external excursory position 25, helicoidal elements 42 consisting of the impact absorbing mean are in a non-active position; when capsules 30 and tufts 9 rotate and descend into head 1, likewise the helicoidal elements rotate in the same direction 16 and are compressed, charging themselves with a springing action 25a; when capsules 30 and tufts 9 are in the rising phase, helicoidal elements 42, discharge their springing effect pushing the capsules themselves towards the top and carrying out a rotation in direction 18, likewise with the rotation imposed upon capsules 30.