MXPA96003964A - Cer finishing fork - Google Patents

Abstract

The invention relates to a device (1) for isolating and rounding the end of the fixed bristles to a toothbrush head (5) within a finishing region of the bristle (7), comprising: (a) means (42, 43) for holding a toothbrush with bristles fixed thereto, and (b) a bristle finishing fork (1) comprising two elongated teeth (2,3) having tips (10, 10 ') spaced apart distance "A" that defines the width of the bristle strip to be isolated, where starting at the tip (10, 10 '), the distance between the blades increases to a distance "B" that defines the side wall of the region of the bristle (7), so that the fork (1) has a backward and forward movement, so that the tip (10, 10 ') of the teeth (2, 3) can be introduced between the bristles of the toothbrush through a parallel relative movement between the fork (1) and the brush, so that the strip of bristles to be isolated is placed on the toothbrush. to the finishing region of the sow (7); and (c) means (60) to round off the distal ends of the sows placed in the sow finishing region (

Description

FORK FINISHING FORK The present invention relates to a device for isolating the fixed bristles to a toothbrush head and terminating the free ends of such bristles in a generally rounded shape. In particular, the present invention pertains to a fork for separating bristles for use in finishing operations of the ends of the bristles, which impart improved roundness to the finished bristles. In addition, the present invention relates to a device for isolating and rounding the ends of the fixed bristles to a toothbrush head. The use of brushes to clean the teeth is a generally accepted means of maintaining oral hygiene. Consequently, many different styles and types of toothbrushes have been described in the art or are available in the market. The different combinations of bristle stiffness, handle design, brush head profile, bristle contour and the like provide various degrees of cleanliness, comfort, and, unfortunately, damage to teeth and gingival tissue. It is generally known that toothbrushes with high contoured bristles can increase the REF: 23060 function of a toothbrush. Toothbrush patterns have been used with patterns of sinusoidal or high-toothed bristles, as well as various cutting patterns of stepped and flattened bristles. It is also generally known that rounding the ends of individual bristles reduces damage to the teeth and gingival tissue by removing the sharp edges resulting from the cutting operation of the bristles. See, for example, The Optimum Characteristics of Toothbrushes for Personal Oral Hygiene, Dent. Interest items, Vol 70, pp. 697-718 (1948). Placing the free ends of the bristles against an orbital grinder is a common and very effective means of rounding the ends when the free ends of the bristles end up in a common plane. See, for example, US Patent 3,451,173 to Hazelton, issued June 24, 1969, incorporated herein by reference. Unfortunately, the contoured bristle patterns exhibit a rounding of the lower ends when this is done on a simple orbital grinding machine as described in the Hazelton patent. If a bristle grinder is placed to round the ends of the higher bristles, the shorter bristles are not rounded to any significant degree. On the contrary, sufficient penetration of the grinding machine to round the ends of the shorter bristles damages and distorts the ends and the side wall of the longer bristles. Complex grinding systems have been developed to attempt to round off the ends of the bristles after they have been attached to the head of the brush and cut to the desired contour. For example, US Patent 2,227,126 issued to Coo on December 31, 1940, describes a complex combination of contoured rectifying wheels, blades and oscillating movements of the bristles that are not within a common plane. It is also well known in the brush manufacturing industry that brushes containing bundles or tufts of bristles of different lengths can be processed on more than one machine. This has been achieved by plowing decks or tufts of short bristles, cutting them to a height and finishing the ends if desired, followed by the increment of the tufting, cutting and finishing steps for each size of the larger tuft. This procedure is slow, and very expensive from the point of view of capital investment since several machines are required to place bristles in each production line. U.S. Patent No. 2,426,328 issued to Wandel et al. on August 26, 1947 describes a thermal process to round the ends of the bristles. Unfortunately, the thermal process, especially for a contoured brush pattern is a very random process. The thickness of the ends of the bristles or fusion of the ends of the bristles with each other is a typical result. Both characteristics are undesirable in finished toothbrushes. Means have been described for removing such thickenings or fusions, such as with steel brushes. However, such removal techniques tend to produce tufts of bristles where the tips of the individual bristles do not have sufficiently uniform rounded ends. In German registered design number 1 931 527 (issued to E. Steinebrunner and Co. Machine Works) a device is described in which the bristles of a toothbrush can be cut into different lengths without readjusting the machine. This requires a combination of two serrated cutting heads, arranged one on top of the other. Therefore, two special serrated cutting heads must be combined in a very specific way for each type of brush. A new type of brush with a different arrangement of high and low parts of the material of the bristle, requires a relatively tedious change in the arrangement of the combined toothed cutting heads, which consumes time and can only be carried out by expert technicians. The most common and cheapest method of processing toothbrushes with bristles of various heights involves using a means of insulating bristles of a particular height during each step of the process. Typically, this is done by means of a template, protector or paddle to protect the non-insulated bristles while the isolated bristles are subjected to a processing step. The German Patent Application 1 532 773 (awarded to Gottlieb Ebser) describes a device having an elongated deflection template (7h) which moves from below upwards of the head of a toothbrush, diverting the bristles out of contact with the rows of selected bristles to be isolated In this way, the isolated bristles could be processed without disturbing the deflected bristles. This patent also describes two turndown dishes (8i and 8h), which wrap around and embrace the outer rows of bristles, while cutting them at a specific height. This patent seems to be silent on the use of rounding of the ends. German Patent 3 415 870 (granted to Anton Zahoransky) describes a machine for treating tufts of bristles and brushes by cutting or flattening them. In this process pressure is exerted on the ends of the tufts of larger bristles by means of a pressure piece of u-shaped cross-section (8). In this way, pushing the larger bristles and leaving them confined inside the pressure piece to retain the bristles, in u-shape. European Patent 0 078 569 (granted to G. B. Boucherie, n.v.) is related to a device for separating rows of brush tufts. The device uses a spacer similar to a fork with two similar protruding blades. The fork is inserted through a parallel movement between the blade and the brush so that at least one row of tufts of the brush can curl laterally outwards. In this way, the non-displaced bristles can be processed in a cutting and rounding operation of the ends. Forks of this type are not novel in the toothbrush manufacturing technique, US Patent 132,031 to J. Stone (issued October 8, 1872) discloses a toothbrush cutter using a bristle holder in the shape of a toothbrush. of fork (E) to hold the bristles to be treated in a cutting operation in place. Finally, US Pat. No. 5,143,425 describes a device for cutting the bristles of a toothbrush at different lengths in different selected areas of a tuft pattern. This device uses a protective member, which moves down on the bristles to be isolated. The protective member also comprises ramp means, which help to push or open the bristles away from the insulated bristles. Surprisingly, the applicant has discovered a novel and improved fork for moving the bristles of a toothbrush. This fork is particularly suitable for the finishing operations of the ends of the toothbrush bristles, for example, rounding of the ends. Accordingly, an object of the present invention is to provide a bristle finishing fork for rounding the ends of the bristles of the toothbrushes attached to a head, which have been cut at different heights. A further object of the invention is to provide a device that allows the separation of the bristles from the toothbrush into finely delineated areas to finish the bristles. A further object of the present invention is to provide a device for isolating and rounding the ends of the fixed bristles to the head of a toothbrush, wherein the bristles are cut to different lengths. This device isolates the bristles of a particular length, terminates them and then isolates them increasingly and then progresses to finish the bristles of other lengths in subsequent growing operations. These and other objects will be clear from the following: The present invention relates to a bristle finishing fork for isolating the fixed bristles to a toothbrush head within a bristle finishing region comprising two elongated teeth which have separate tips a distance "A" that defines the width of the strip of bristles to be isolated, where starting at such point, the distance between the teeth increases to a distance "B" that defines the lateral wall of the region of finished of the sow. The present invention also relates to a two-tooth bristle finishing fork, comprising: (a) a base plate; (b) two elongated teeth having a tip end and a terminal end, the teeth are connected to the bplate at their terminal ends, where the teeth are spaced a distance "A" defining the width of the strip bristles to be isolated, where starting at the tip of the tooth, the distance between the blades incre to a distance "B". The present invention further relates to a device for isolating and rounding the ends of the fixed bristles to a toothbrush head within a bristle finishing region, comprising: (a) means for holding a toothbrush with bristles fixed to him; and (b) a bristle finishing fork, comprising two elongated teeth having spaced apart points a distance "A" that defines the width of the die desired to be isolated, wherein starting at the tip, the distance between the blades is incre to a distance "B" that defines the side wall of the finishing region of the bristles, so that the fork has a backward and forward movement, in such a way that the tip of the teeth can be introduced between the bristles of the toothbrush through a parallel relative movement between the fork and the brush, so that the rows of bristles to be isolated are placed in the finishing region of the bristles; and (c) means for rounding the distal ends of the bristles placed in the finishing region of the bristles. Also, the present invention relates to a method for isolating and rounding the ends of a particular region of bristles that have been attached to a toothbrush head. Although the specification concludes with the claims that specifically state and claim the related matter forming the present invention, it is believed that the invention will be better understood from the following description and drawings in which Figure 1 is a top plan view of the invention. a bristle finishing fork according to the present invention; Figure 2 is a raised lower view of the bristle finishing fork according to Figure 1; Figure 3 is an end view of the bristle finishing fork of Figure 1, when viewed from the tip; Figure 4 is an end view of the bristle finishing fork of Figure 1, when viewed from the end of the bplate; Figure 5 is a left side view of the bristle finishing fork of Figure 1 inserted into the bristles of a toothbrush. (The view on the right side is a mirror image of Figure 5); Figure 6 is a cross-sectional view of the fork of Figure 5 taken from the cross-section I-I of Figure 1; Figure 7 is a schematic view of the previous one of a device according to the present invention; Figure 8 is a side view of the device of Figure 7; Figure 9 is a view similar to that of Figure 7, but in a second characteristic position; Figure 10 is a cross-sectional view of section II-II of Figure 9. This view shows the deflection of non-insulated bristles; Figure 11 is a view similar to that of Figure 10, but describing an orbital grinder terminating the ends of the isolated bristles; Figure 12 shows a top plan view and schematic of the different stages of production on only one toothbrush machine with bristles cut at five different heights; Figure 13 is a view similar to that of Figure 12, but in a second characteristic position. During this phase of the process the forks are engaged, and an orbital grinder is used to round the ends of the bristles that have been isolated. The orbital grinding machine is described by the line ""; Figure 14 is a view similar to that of Figures 12 and 13, but in a third characteristic position. In this position the forks are disassembled and the bristles are free to move to the next ordered position; and Figure 15 shows the toothbrush produced by the process described in Figures 12, 13 and 14. Figure 1 discloses a bristle finishing fork 1 according to the present invention. The fork is comprised of two elongated teeth, 2 and 3, which have tips, 10 and 10 'separated by a distance "A". During the operation this fork has a backward and forward movement relative to the head of a toothbrush 5, as described by the arrow 4, such that the tips 10 and 10 'of the teeth 2 and 3 can to be inserted between the bristles of the toothbrush through a parallel relative movement between the fork 1 and the brush 5. The teeth, 2 and 3, are generally divided into a penetration region 6 and a finishing region of the bristles 7. Those teeth are further comprised of an edge surface of the inner blade 8 and an edge surface of the outer blade 9, wherein the outer blade surfaces are effective to open the bristles away from the finishing region of the bristles. . As can be seen from Figures 1 and 2, the edge surface of the inner blade 8 and the edge surface of the outer blade 9 intersect at the tips 10 and 10 'of the tooth. Furthermore, the end-to-end separation (10 to 10 ') is what defines the distance A. An important feature of the present invention lies in the characteristic that the distance between the teeth increases from the tip to a distance "B". "which defines the lateral wall of the finishing region of the bristles. Applicants have discovered that by increasing this distance the bristles are allowed to tilt during the end rounding process; thereby providing improved rounding of the ends of the bristles. To assist in the transition of the sow through the penetration region and in the finishing region, and vice versa, an arched transition 11 is preferably used between the penetration region 6 and the finishing regions 7. As can be seen from of the Figures, the edge surface of the inner blade 8 and the edge surface of the outer blade 9, intersect at the tip 10 to form an acute angle a. Preferably, the edge surface of the inner blade 8 and the edge surface of the outer blade 9 intersect at the tip 10 to form an angle of approximately 50 degrees (a). The base plate 12 has two perforations, 20 and 20 ', which are used as fixing means for the fork. Any means of attachment known to those skilled in the art can be used. Typically, the fork is fixed to a sliding member similar to a cam or to a mechanical insertion device such as a pneumatic drive device, an electric drive device or a magnetic drive device. Figure 3 shows a view from the tip end of the bristle fork of Figures 1 and 2. Deployed in a prominent manner are the surfaces 15 and 16, which are inclined from the separated region AA 60. Tilt aids the displacement of the bristles from the finished region and prevents their sliding back towards the region. Figure 4 shows a view from the end of the base plate. The thicknesses of these forks are typically greater than 0.5 mm and should preferably be approximately 2 mm. Figure 5 is a left side view of the fork of Figure 1. As can be seen, the brush side 61 (bottom) of the fork has a point 13, which extends in the direction of the brush. This point finds the bristles first and is the initial separation means directing the non-insulated bristles from the finishing region of the bristles 7. Figure 6 is a cross-sectional view through the front lines II of Figure 1. As can be seen, the teeth are preferably comprised of the lower surfaces 15 and 16 to prevent the fibers from sliding open towards the finishing region of the bristles 7 (defined here by the spacing, B "). The lower surfaces 15 and 16 intersect the surface of the edge of the inner blade 8 to form an acute angle ß when viewed from the tip. Applicants have found that an acute angle of about 75 degrees provides the best opening and retention results. In Figures 7 to 14, the device according to the invention mainly consists of a bristle finishing fork 1, which is fixed on a carriage, guide or similar means, so that this guide 30 can move in parallel movement in relation to the fork and the bristles to be isolated 40 (shaded). Applicants admit that such carriage, guide or similar means can be operated by any mechanical means known in the art, such as, for example, by means of a pneumatic drive device, a mechanical drive device, springs, mechanical cams, etc. . Also, in the alternative, the fork could be stationary and the brush could move in and out. Placed on the front part of the fork 1, a support 41 is provided, on which the suitable fastening means 42 and 43 are mounted, which serve for the purpose of suitably holding a brush body 31 against a thrust bearing with respect to the fork 1, whereby, in the present case, the body of the brush has a region of bristles to be isolated 40 (shaded) and regions of bristles to be displaced 44 and 45. The limits 2 and 3 show in its front end a beveled face tip 50 and 50 ', to assist the movement of the teeth from the position of Figure 7 to the position of Figure 9. The outer bristles 44 and 45 move through the penetration of the teeth. teeth between regions 44/40 and 45/40, as clearly shown in Figures 10 and 11. Those external bristles are pushed towards the outer side, whereby the teeth have a width that is such that the upper portions 52 and 53 of the rows of hairs of The brush 44 and 45 will be brought to a lower level than the upper parts 55 of the bristles in the region to be isolated 40. In the position according to Figure 7 the different bristles of the brush are in their normal state, so that it is sufficient to move the guide 30 in any suitable manner so that the teeth 2 and 3 move towards the body of the brush, whereby it is obtained that the beveled faces 50, 16 and 17 of the blades will exert an action on the bristles not insulated 44 and 45 while, due to the internal vertical face 8 internal of the teeth, the adjacent bristles 40 will not be influenced. The displaced bristles 44 and 45 will be maintained in the displaced position by the action of the lower surfaces 15 and 16. The beveled face at the tip 50 and 50 'and the lower surface 16 and 17 are made such that the tip of the teeth 13 penetrate exactly between the bristles at the base of those bristles, so that the separation of the bristles becomes easier. Preferably, this penetration occurs at a transition point between bristles of different heights; thus retaining the original outline of the cutting pattern of the bristles. When the blade is engaged within the brush section, as in Figure 9, the tips 10 and 10 'of the teeth are spaced a distance A. This distance between the teeth defines the minimum width of the strip or row of bristles to sec sec 40. As the fork continues to penetrate the head, the insulated bristles 40 slide towards the finishing region of the bristles 7. As can be seen from the Figures, the penetration region 7 is wider and slightly larger than the actual displacement of the bristles on the head. This provides finishing characteristics of the upper bristles, when the bristles are finished in a rounding operation of the ends. The rounding operations of the ends involve grinding or abrading the ends of the bristles to form a rounded appearance. For an additional discussion of the rounding of the extremes, and the characteristic determinations used to quantify such, please see: Silverstone &; Featherstone, Examination of End Roundina Pattern of Toothbrush Bristles, Gerodontics, 4: 2, pp. 45-62 (1988); Nygaard-Ostby et al., Access to I terproximal Tooth Surfaces by Different Bristle Designs and Stiffnesses of Toothbrushes, Scand. J. Dent. Res., 87: 424-430 (1979); and Breitenmoser et al., Damaging Effects of Toothbrush Bristle End Form of Gingiva, J. Periodontol. , 50 (4), pp. 212-216 (April 1979), all incorporated herein by reference.

The rounding / abrasion process is typically carried out by the use of elliptical orbital rectifiers similar to those described in USPatent 3,451,173 to Hazelton, issued June 24, 1969, incorporated herein by reference, or by way of a band or drum sanders. Preferably, rotating band rectifiers are used in conjunction with the present invention as shown in Figure 11. As can be seen, the orbital rectifier 60 is brought into contact with the tips 55 of the insulated bristles 40, thus causing them to oscillate. , move in orbit and freely within the finishing region of the bristles 7. Figures 12, 13 and 14, schematically show how the device according to the invention can be used to further treat the brush bristles prior to the tufting of the bristles. It should be noted that the tufting of the brush hairs of different lengths is generally carried out by transporting bristles of different lengths from two containers or cutting them in place using multiple cutting operations. Figures 12, 13 and 14 show schematically 5 work stations, 101, 102, 103, 104 and 105, respectively, so that in the stations 101, 102, 103, and 104, the finishing fork is used. bristles for insulating particular bristles according to the present invention. As can be shown in Figure 12, the brush heads 111, 112, 113, 114 and 115 are indexed in their position within each work station. The regions that will be isolated and rounded at each workstation are shown shaded at 121, 122, 122 ', 123, 123', 124, 124 ', 125 and 125'. The critical dimensions of the process forks are described in the following table: Distance A Distance B Fork 133 1.4 mm 4 mm Fork 134 2.1 mm 4 mm Fork 135 2.8 mm 4 mm Fork 136 3.5 mm 4 mm Optionally, distances A and B can be proportional. In this way the dimensions described above can be modified as follows: Distance A Distance B Fork 133 1.4 mm 2.9 mm Fork 134 2.1 mm 3.6 mm Fork 135 2.8 mm 4.3 mm Fork 136 3.5 mm 5.0 mm Figure 13 shows schematically the next step in the processing scheme by which the forks 133, 134, 135 and 136 are brought into contact with the bristles, thereby opening the bristles out of the shaded regions away from the region of finished of the bristles 7. Once the fork and the bristles have been coupled and the insulated bristles (121, 122, 122 ', 123, 123', 124, 124 ', 125, and 125') are placed inside the In the finished region, the orbital rectifiers are brought into contact with the tips of the exposed bristles, see the dotted circles on the processing region in Figure 13. Figure 14 schematically describes the final step in the processing scheme by which the hairpins (133, 134, 135 and 136) are decoupled from the region of the bristles. From this point, the brushes are indexed to the next step of the process whereby the head of the brush 111 moves towards the work station 102, the brush head 112 moves towards the work station 102, the brush head 113 it moves towards the work station 104, the brush head 114 moves towards the work station 105, and the brush head 115 moves towards the package. Figure 15 describes the toothbrush head 48 produced by the process according to the diagrams of Figures 12 and 14. It is interesting to note that the slight increase in the width of the separation A with each rounding of one end, progressive, on the described V-shaped cutting sleeve retains the V-like groove in the brush. It is clear that the present invention is not entirely limited to the embodiments described as in the example and as shown in the accompanying drawings, but such a device can be carried out in various forms and dimensions without departing from the scope of the invention. For example, the penetration of the fork does not need to be from the end of the handle as described in the figures. Alternatively, the penetration of the fork could be from an end other than that of the handle or at any angle relative to the head. 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, as property contained in the following:

Claims (19)

1. A bristle finishing fork for insulating the bristles fixed to a toothbrush head within a bristle finishing region, characterized in that it comprises at least two elongated teeth having spaced tips a distance "A" defining the width of the toothbrush. row of bristles to be isolated, where starting from the tip, the distance between the teeth increases up to a distance "B" that defines the side wall of the finishing region of the bristles.

The bristle finishing fork according to claim 1, characterized in that the teeth are further comprised of internal blade edge surfaces, which are facing each other and external blade edge surfaces, where the edge surfaces of The external blade is effective to open the bristles from the finishing region of the bristles.

The bristle finishing fork according to claim 2, characterized in that the edge surfaces of the inner blade are comprised of a penetration region close to the tip and a bristle finishing region distal to the tip.

4. The bristle finishing fork according to claim 3, characterized in that the penetration and termination regions of each edge surface of the inner blade are generally parallel and are connected by means of an arcuate transition.

The bristle finishing fork according to claim 2, characterized in that the edge surface of the inner blade and the edge surface of the outer blade intersect at the tip to form a sharp angle.

The bristle finishing fork according to claim 5, characterized in that the edge surface of the inner blade and the edge surface of the outer blade intersect at the tip to form an angle of about 50 °.

7. The bristle finishing fork according to claim 5, characterized in that the teeth are furthermore comprised of a lower surface to prevent the bristles from being opened by sliding towards the finishing region of the bristles.

The bristle finishing fork according to claim 7, characterized in that the lower surface intersects the edge surface of the inner blade to form a sharp angle when viewed from the tip.

The bristle finishing fork according to claim 8, characterized in that the lower surface intersects the edge surface of the inner blade to form an angle of approximately 75 ° when viewed from the tip.

A device for isolating and rounding the ends of the bristles attached to a toothbrush head within a bristle finishing region, characterized in that it comprises: (a) means for holding the toothbrush with the bristles attached thereto; and (b) a bristle finishing fork comprising at least two elongated teeth having spaced apart points a distance "A" which defines the width of the row of bristles to be isolated, wherein starting from the tip, the distance between The blades are increased to a distance "B" that defines the side wall of the finishing region of the bristles, so that the fork has a backward and forward movement, in such a way that the tips of the teeth can be introduced between the bristles of the toothbrush through a parallel relative movement between the fork and the brush, so that the rows of bristles to be isolated are placed in the finishing region of the bristles; and (c) means for rounding the distal ends of the bristles placed in the finishing region of the bristles.

11. The device for insulating and rounding the ends of the bristles fixed to a toothbrush head in accordance with claim 10, characterized in that the isolated bristles are of a length that is different from that of the bristles located outside the finishing region of the bristles.

The device for insulating and rounding the ends of the bristles fixed to a toothbrush head according to claim 11, characterized in that the teeth are further comprised of surfaces of the edge of the inner blade that are facing each other and surfaces of the edge of the outer blade, wherein the outer blade edge surfaces are effective to open the bristles from the finished region of the bristles.

The device for insulating and rounding the ends of the bristles fixed to a toothbrush head according to claim 12, characterized in that the surface of the edge of the inner blade and the edge surface of the outer blade intersect in the tip to form an acute angle.

14. The device for insulating and rounding the ends of the bristles fixed to a toothbrush head according to claim 13, characterized in that the teeth are further comprised of a lower surface to prevent the bristles from sliding open towards the region of finishing of the bristles.

15. The device for insulating and rounding the ends of the bristles fixed to a toothbrush head according to claim 14, characterized in that the inner surface intersects the surface of the edge of the inner blade to form an acute angle when See from the tip.

16. The device for insulating and rounding the ends of the bristles fixed to a toothbrush head according to claim 15, characterized in that the front fork is fixed on a guide, which can obtain a backward and forward movement with respect to the brush.

17. The device for insulating and rounding the ends of the bristles fixed to a toothbrush head according to claim 15, characterized in that the above means for holding the toothbrush are fixed on a guide, which can obtain movement backwards and forwards, with respect to the fork.

18. A method for isolating and rounding the ends of the bristles attached to a toothbrush head, characterized in that it comprises the steps of: (1) providing a device for insulating and rounding the ends of the bristles attached to a brush head of teeth with a bristle finishing region, comprising: (a) means for holding the toothbrush with the bristles attached thereto; and (b) a bristle finishing fork comprising at least two elongated teeth having spaced apart points a distance "A" that defines the width of the row of bristles to be isolated, wherein starting from the tip, the distance between The blades are increased up to a distance "B" which defines the side wall of the finishing region of the bristles, so that the fork has a backward and forward movement, in such a way that the tip of the teeth can be introduced between the bristles of the toothbrush through a parallel relative movement between the fork and the brush, so that the row of bristles to be isolated is placed in the finishing region of the bristles; and (c) means for rounding the distal ends of the bristles positioned in the finishing region of the bristles; (2) attaching a toothbrush with a plurality of bristles attached to the head within the means for holding a toothbrush; (3) insert the fork between the bristles of the toothbrush; and (4) round off the distal ends of the sows placed in the finishing region of the sows. The method according to claim 18, characterized in that it further comprises the steps of: (5) providing a second device for isolating and rounding the ends of the bristles attached to a toothbrush head within a region of the bristles, comprising: (a) means for holding a toothbrush with the bristles attached thereto; and (b) a bristle finishing fork comprising at least two elongated teeth having spaced apart points a distance, A "which defines the width of the row of bristles to be isolated, wherein starting from the tip, the distance between the bristles The blades are increased to a distance "B" that defines the side wall of the finishing region of the bristles, so that the fork has a forward and backward movement, in such a way that the tip of the teeth can be introduced between the bristles of the toothbrush through a parallel relative movement between the fork and the brush, so that the row of bristles to be isolated are placed in the finishing region of the bristles and so the distance "A" of this hairpin is different from the distance "A" of step (1), and (c) means for rounding the distal ends of the bristles placed in the finishing region of the bristles, and (6) coupling a toothbrush with a plurality of bristles fixed to the head inside the means for holding a toothbrush in a second device; (7) inserting the fork between the bristles of the toothbrush in the second device; and (8) rounding the distal ends of the bristles placed in the finishing region of the bristles of the second device. FORK FINISHING FORK SUMMARY OF THE INVENTION The invention relates to a device (1) for isolating and rounding the end of the fixed bristles to a toothbrush head (5) within a finishing region of the bristle (7), comprising: (a) means (42, 43) to hold a toothbrush with bristles attached thereto; and (b) a bristle finishing fork (1) comprising two elongated teeth (2, 3) having tips (10, 10 ') spaced a distance "A" defining the width of the strip of bristle to be isolated, where starting at the tip (10, 10 '), the distance between the blades increases to a distance "B" which defines the side wall of the finishing region of the bristle (7), so that the fork (1) has a backward and forward movement , so that the tip (10, 10 ') of the teeth (2, 3) can be inserted between the bristles of the toothbrush through a parallel relative movement between the fork (1) and the brush, so that the strip of bristles to be isolated is placed in the finished region of the sow (7); and (c) means (60) for rounding the distal ends of the bristles placed in the finishing region of the bristle (7).