MXPA98002010A - Dental brush and process for your manufacture - Google Patents

Abstract

The present invention relates to a toothbrush having a brush head and plastic bristles, optionally combined in groups, fixed thereto and in which at least some bristles have a profile on their circumferential surface. In the case of the resistance characteristics without change of the bristles, in order to obtain an increased action of cleaning and massage, the bristles have a propeller like the profile. The bristles may comprise a core and at least one helix running on the circumferential surface. For the manufacture of the toothbrush, it is possible to extrude and then twist the profiled monofilament or a monofilament with axially parallel protrusions and then fix the torsion. It is also possible to coextrude a monofilament made of a plastic with protrusions made of a plastic having other characteristics that run on its circumferential surface, followed by the twisting of the coextruded compound and the fixing of the torsion.

Description

TOOTHBRUSH AND PROCESS FOR ITS MANUFACTURE DESCRIPTION OF THE INVENTION The invention relates to a toothbrush with a brush head and plastic bristles, optionally combined in groups, fixed thereto, in which at least some of the bristles have a profile on their circumferential surface, as well as with a method for the manufacture of a bristle for a toothbrush. In the same way, the invention is usable in an interdental cleaner, which is expressly included. In the case of toothbrushes, operated either manually or electrically, the bristles conventionally comprise extruded monofilaments with a circular cross-section. Other cross sections have already been proposed. The cleaning action of such toothbrushes, as well as the desired massage action of the gums, takes place almost exclusively through the ends of the bristles which are rounded to avoid recession of the gum and damage to it. For this purpose, the end of the sow must satisfy two opposite requirements, specifically on the one hand exert an adequate brushing action on the tooth, and on the other hand, carry out a restricted massage of the gums. The cleaning of the surfaces of the tooth and the spaces between the teeth, which is vital, consequently is not adequate due to the commitments that are made. Numerous attempts have been made to incorporate the circumferential surface of the bristle by profiling it in a brush process and consequently increasing the cleaning action. Thus, it is known (DE 31 16 189) to provide the bristle with different separate thickenings, which form additional brush edges. It is hardly possible to manufacture rotationally such a brush, if it is kept in mind that the bristles are conventionally produced by spinning or extrusion. Admitting that it is theoretically possible to carry out changes in the cross section in the extrusion direction that allow a sow to be produced by extrusion, the monofilaments produced by extrusion must be subsequently finished and specifically stretched and heat stabilized, to provide the sow desired doubles capacity and straightening ability. Such stretching in the case of injection-molded or extruded bristles with separate thickenings only leads to a bristle that is stretched and restricted in the vicinity of the narrower cross-sections between the thickenings, while the latter are not altered. Such a sow would be completely unusable. Even if the possibility of providing a sow with the necessary characteristics was demonstrated, there would be a risk that the sow with the thickened parts will lodge in the interdental spaces and when pulled it could tear or detach the head of the sow or damage the gums in the interdental space, so it would be particularly dangerous due to inadequate adherence to the dental narrowing. The problem of the invention is to provide a toothbrush with shaped bristles, which, in the case of strength characteristics without change of the bristles, have an improved cleaning and massage action and which can be manufactured cheaply. According to the invention, this problem is solved with the bristles having a propeller-like profile. Such bristles can be produced by extrusion and finishing in the same manner as a conventional sow. It has the advantage that, in addition, at the end of the sow the head of the propeller or its transition to the flanks and the real flanks form additional brush edges, which reinforce the cleaning action of the surfaces of the teeth and spaces between the teeth. teeth, without damaging the gums. Even if such bristles penetrate the interdental spaces, bristling of the bristles can not occur, because there are no radial constrictions. Also, pulling the propeller can turn or twist, so that no extraction forces act on the sow which may be greater than those of conventional sows. Even if the circumferential surface of such bristles rubs on the gums, it produces a massage action due to the propeller. It is known in the recognized manner in the case of cylindrical brushes for car wash installations (DE-U-93 19 214) to use profiled bristles, which are also twisted. However, in this case, with a propeller having an extremely large pitch of several centimeters of bristle length, a gentle treatment must be provided and the opposite demands (brushing and restricted massage) are not satisfied. Advantageously, at least part of the bristles have a single or multiple passage, or a helical strand so that the active surfaces during cleaning are enlarged and actions are obtained simultaneously in different directions. Another preferred development is characterized in that the bristles comprise a core and at least one helix that passes over the circumferential surface. The core provides the sow with the standard features (Bending capacity, and straightening capacity, etc.). It is also advantageous if the propeller has a trapezoidal cross section, preferably the head of the propeller is flattened or rounded, so that sharp edges are not present. This can be carried out during the extrusion or later by mechanical or thermal action. For certain fields of use, it must be ensured that the user recognizes that such brushes have spiral bristles that act particularly abrasively and do not misuse the same treatment for sensitive gums. Therefore, according to a further development of the invention, at least one projection has a different color with respect to the core. The plastic of the projection can be dyed with pigments. Since the pigment particles are harder than the plastic matrix, the helix can have some aversive action as a result of dyeing. Preferably, the core and at least one projection are made of different materials. Therefore, a projection can be adapted to specific conditions of use, particularly with respect to its hardness. Information can be provided to the user regarding the brushing characteristics of the particular brush by a different color design of the core and the protrusions. Such projections can be easily obtained when the monofilament has a polygonal section, preferably square. Subsequently, after twisting, each edge forms a projection. It is necessary with certain brushes that the bristles have a predetermined rigidity or elasticity. A rigidity adaptation can be obtained, according to a preferred development of the invention, if the core has an outer core and a sheath, which surrounds the latter, made of different materials. By choosing the materials for the outer core and sheath, the stiffness and elasticity of the bristles, on the one hand, and the action in the case of dental care on the other, can be altered and can vary in a desired manner. The projections on the cover can be made from the material of the last one or they can be made from a different material. Preferably, the bristles comprise a profiled and subsequently twisted monofilament, the profile areas projecting beyond a fictitious circular cross section and whose center forms the torsion axis, in each case forming a helix. The brushing action depends, for example, on the torsion measurement in relation to the effective length of a bristle or a bristle material, that is, of the passage of the helix formed as a result of the twisting. It has been found that the pitch of the helix should not be more than twice the effective length of the bristle, so that the effective length is provided with a helix extending more than 180 °. However, normally the helix has a smaller pitch that extends to the diameter of the bristle material. According to a further development of the invention, the monofilament or the monofilaments are made of an elastic plastic. In this way, the bristles made of a bristle material can be expanded longitudinally, which leads to a reduction in their diameter, so that, for example, after insertion in an interdental state, they can be more easily removed therefrom. and not get stuck in it. Jamming is prevented to the extent that the bristle can turn when it is removed. If necessary, the bristles may only have one part in the form of a helix in their length. In order to adapt the action of a brush to provide frame conditions, spiral bristles with bristles of other configurations can be combined and processed together. For the manufacture of a bristle for a toothbrush having the aforementioned construction, the invention proposes that a monofilament be extruded with at least one projection axially parallel, twisted and then the torsion fixed. The bristles can then be manufactured by cutting to length from a continuous strand. Another method comprises a monofilament made of a plastic that is co-extruded together with the projections running on its circumferential surface made of a plastic having other characteristics, followed by the twisting of the coextruded compound and finally torsional fixation. This method also allows the continuous manufacture of the bristle material. The plastic that forms the helix can also be adapted to the proposed use. For example, the core can be made of a plastic conventionally used for bristles, while the plastic used for the helix is made of a softer or harder material, and can be provided with abrasive fillers. The plastic that forms the helical protrusions can also have a different color, so that it allows a functional indication. The core can also be made of different materials in zones, so that it adapts the sow to its proposed use. The core has an inner area and a sheath that it surrounds the interior area made of different materials and which are coextruded. Another manufacturing possibility is to extrude at least two monofilaments, which are then twisted and then the torsion is fixed. During extrusion or after twisting, the monofilaments can be interconnected in a non-releasable manner. The bristle according to the invention also offers the possibility that the extruded monofilament or the co-extruded compound be stretched before twisting and optionally stabilized in order to provide the sow with the helix the necessary characteristics for the bristles used in brushes. dental Finally, as in conventional bristles, it is advantageous if the monofilament or the coextruded compound, after twisting, is heat stabilized and then stored for 24 to 48 h. In the case of toothbrushes, the ends of the bristles should be rounded after being cut in order to avoid damage to the teeth and alterations to the gums. This advantageously takes place by melting the surface of the ends of the bristles, because the ends of the thin-walled helix melt before the core and consequently the cutting edges initially change shape.

A sow made according to one of the methods mentioned above is also suitable eminently for interdental cleaners. In the case of an interdental cleaner other advantages arise, if it is only twisted in an area of its length. The non-twisted area has smaller cross-sectional dimensions and can consequently be more easily inserted into an interdental space. The introduction can be facilitated more if the non-twisted area in at least one area has a flattened cross section, for example, by pressing. In order to ensure a completely satisfactory fixation and resistance to the removal of the bristles from the body of the brush, the bristles, individually or in groups, melt on their clamping side on the head and are fixed thereto in the body of the brush . As a result, the end of the clamping side has a uniform spherical or lenticular cross section which allows a completely satisfactory fixation on the head of the brush. The invention is described in more detail below in relation to the embodiments and the accompanying drawings, in which it is shown: Figure 1 is a diagrammatic side view of a toothbrush.

Figure 2 is a detail with a greater step-by-step detail of a sow. Figures 3 to 5 are different cross-sectional shapes of an extruded monofilament. Figures 6 to 11 are different cross-sectional views of a co-extruded composite. The toothbrush according to Figure 1 has a head 30 and a handle 31, which is interconnected by means of a flexible neck 32. The head 30, the handle 31 and the neck 32 are injection molded from plastic in one piece. The bristles in the form of groups 33 are fixed to the head 30. The groups 33 are only indicated diagrammatically and in each case comprise a plurality of plastic bristles which are fixed by welding, injection or mechanically to the head 30. The figure 2 shows a single bristle 1 of a group 33. It is constituted of a circular cylindrical core 2, whose total circumferential surface is provided with a helix 4 of two steps, with the two helices 5, 6. Each propeller 5, 6 has a head 7 or 8 flattened or rounded. Such a toothbrush bristle, for example, may have an outer diameter of about 0.2 mm, the core 2 may have a diameter of about 0.1 to 0.15 mm. For the length of bristle of up to 1.5 cm conventionally used for toothbrushes, the helix has a pitch of 2 to 6. The bristle according to Figure 2 can be manufactured in different ways, for example, it can be extruded, stretched, twist and finally heat fix the. monofilament 9 according to figure 3, with a core 10 and two projections 11, 12, placed diametrically so as to provide a double-pitch helix, according to figure 2. Figure 4 shows an extruded monofilament 9 with a cross section approximately triangular formed by a core 13 and three projections 14, 15, 16. Figure 5 shows a monofilament 9 with a cross section in the form of a cross, which once again has a core 17 and four projections 18, 19, 20 and 21 placed symmetrically. The torsion axis in all the modalities coincides with the axis of the core 2. The monofilament can also have a substantially rectangular cross section, for example, square, the area of the core near the center and the four corner regions forming the projections. Figures 6 to 8 show substantially the same cross-sectional shapes as Figures 3 to 5, but in this case the circular cylindrical cores 10, 13 and 17 are co-extruded with projections 11, 12 or 14 to 16 or 18 to 21. The extruded monofilament or co-extruded composite is then stretched, twisted and stabilized with heat-and stored for 1 to 2 days. Figures 9 to 11 show cross-sectional shapes similar to Figures 6 to 8, but the cores 10, 13 and 17 have an outer core 10a, 13a and 17a, which surrounds the final covers 10b, 13, and 17b. The outer core and the liner are made of different materials, the projections 11, 12 or 14 to 16 or 18 to 21 are made of an additional material. The outer core is co-extruded with the lining and the projections, and subsequently the work is carried out in the indicated manner. The outer core 10a, 13a and 17a can be made of a typical plastic for bristles for toothbrush, in order to ensure all the positive strength characteristics of a conventional bristle, while the plastic materials of the lining 10b, 13b, 17b and for projections 11, 12 or 14 to 16 or 18 to 21 can be adapted to the desired cleaning and / or massage sections. As can be obtained in particular from figures 3 to 11 and as described in relation to figure 2, the head of the bristles is flattened or rounded. After cutting the bristles at a length from the continuous material, the ends of the use side are rounded, preferably by surface prefusion, while the ends of the clamping side melt individually or in groups at the head. Instead of the cross section shown, the bristle or the monofilament of which it is formed can also have a rectangular and preferably square cross section. After twisting, the edges of the cross section in each case form a projection. It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects to which it relates. Having described the invention as above, property is claimed as contained in the following:

Claims (15)

1. A toothbrush with a brush head and with plastic bristles optionally combined in groups, attached thereto, in which at least some of the bristles have a circumferential surface and a profile in the shape of a helix obtained by twisting a profiled monofilament, characterized in that the bristles comprise a core and at least one helix that passes over the circumferential surface and has three to five turns per cm in length and the head of the helix is rounded.

2. The toothbrush according to claim 1, characterized in that at least part of the bristles has a single pitch or multiple pitch propeller.

3. The toothbrush according to claim 1, characterized in that the helix has a substantially trapezoidal cross section.

4. The toothbrush according to claim 1, characterized in that the helix and the core have different colors.

5. The toothbrush according to claim 1, characterized in that the helix and the core are made of different materials.

6. The toothbrush according to claim 1, characterized in that the core has an outer core and a lining surrounding the outer core made of different materials.

7. The toothbrush according to claim 1, characterized in that the monofilament or monofilaments are made of elastic plastic.

8. The toothbrush according to claim 1, characterized in that the bristle has only one helix over part of its length.

9. A method for manufacturing a plastic bristle for a toothbrush according to one of claims 1 to 8, characterized in that a profiled monofilament or a monofilament with at least one axially parallel projection is extruded, and then twisted about less part of its length and the torsion is fixed.

10. The method for manufacturing a plaster bristle for a toothbrush according to one of claims 4 to 8, characterized in that a monofilament manufactured in a plastic is coextruded together with the projections made of a plastic having different characteristics, and then the The co-extruded composite is twisted over at least part of its length and the twist is set.

11. The method according to claim 9 or 10, characterized in that the extruded monofilament or the extruded compound is stretched before subjecting it to torsion.

12. The method according to claim 9 or 10, characterized in that the monofilament or the coextruded compound is thermally stabilized after being subjected to torsion.

13. The method according to claim 12, characterized in that the twisted monofilament or compound is stored at an optionally increased temperature after thermal stabilization.

14. The method according to claim 9 or 10, characterized in that the end of the use side of each sow is rounded by surface melting.

15. The method according to claim 9 or 10, characterized in that the bristles are fused individually and in groups on their clamping side to the head and are fixed thereon, in the body of the brush.