EP0054484B2 - Method of treating the ends of natural bristles for tooth brushes - Google Patents

Abstract

1. Method of treating the free ends of natural bristles used for the making of tooth brushes, characterised in that it consists of applying the free ends of bristles to a wheel (10) according to a combined relative movement composed of a to-and-fro oscillation (14, 14') of the bristles above the wheel (10) in a plane perpendicular to the grinding plane, the said wheel (10) being rotated (N) about its axis (12), disposed parallel to the grinding plane, and in that the combined relative movement further comprises a simultaneous rotation (n) between the wheel (10) and the bristles, about an axis (13) substantially perpendicular to the grinding plane.

Description

The present invention relates to a method of treatment, and more particularly of filling the medullary canal with natural fibers used in toothbrushes.

Various methods of treating fibers for brushes have already been proposed.

• - d'un balancement en va-et-vient des fibres au-dessus de la meule de part et d'autre d'un plan perpendiculaire au plan de meulage,
• - d'une rotation du support de brosse autour d'un axe perpendiculaire au plan de meulage,
• - d'une rotation de la meule autour d'un axe perpendiculaire au plan de meulage.

Document US-A-3 417 516 describes a process for treating the end of the fibers for a brush which consists in applying the free end of the fibers to a grinding wheel in a combined movement formed simultaneously:

• - a rocking back and forth of the fibers above the grinding wheel on either side of a plane perpendicular to the grinding plane,
• - a rotation of the brush support around an axis perpendicular to the grinding plane,
• - a rotation of the grinding wheel around an axis perpendicular to the grinding plane.

• - d'un balancement en va-et-vient des fibres au-dessus d'une meule, de part et d'autre d'un plan perpendiculaire au plan de meulage,
• - d'un rotation de la meule autour d'un axe perpendiculaire au plan de meulage, ce dit axe étant lui-même animé d'un mouvement de rotation autour d'un second axe perpendiculaire au plan de meulage, et d'une translation de la meule dans le plan de meulage.

The document US Pat. No. 3,063,204 describes a method for treating the free end of brush fibers consisting in applying the latter to a grinding wheel in a combined movement composed simultaneously;

• - a rocking back and forth of the fibers above a grinding wheel, on either side of a plane perpendicular to the grinding plane,
• - a rotation of the grinding wheel around an axis perpendicular to the grinding plane, this axis being itself driven by a rotation movement around a second axis perpendicular to the grinding plane, and a translation of the grinding wheel in the grinding plane.

The natural fibers used for making toothbrushes, such as boar or pig hair from Tchunking, have a general appearance that looks like a mini pipe.

Consequently, all kinds of foreign bodies, for example living or dead microorganisms, food micro-debris, saliva and toothpaste are capable of penetrating inside the medullary canal, through the free end of each of these natural fibers, that is to say the end which is brought into contact with the teeth and gums when brushing.

The object of the present invention is to propose a method for treating the end of natural fibers, making it possible in particular to obstruct the free end of the medullary canal of these fibers in order to prevent any foreign body from entering it.

In this filn, according to the present invention, the process for treating natural fibers used for making toothbrushes, is of the type comprising the steps known per se consisting in applying the free end of the fibers to a grinding wheel in a combined movement composed of a rocking back and forth of the fibers above the grinding wheel on either side of a plane perpendicular to the grinding plane and composed of a simultaneous rotation between the grinding wheel and the fibers, around '' an axis substantially perpendicular to the grinding plane in which the combined movement further comprises the driving in rotation of the grinding wheel around its axis arranged parallel to the grinding plane, and the duration of a back-and-forth rocking of the fibers above the grinding wheel corresponds to the duration of a complete rotation between the fibers and the grinding wheel, in the grinding plane.

The rotation between the fibers and the grinding wheel, around an axis substantially perpendicular to the grinding plane, is advantageously carried out around an axis passing through the axis of rotation of the grinding wheel and situated in the plane of the latter.

According to a characteristic of the invention, the method consists in applying the fibers a first time on the grinding wheel according to the previously defined combined movement, then in spreading the end of the fibers away from the surface of the grinding wheel, and in reapplying the fibers a second time. fibers on it, in the same combined movement.

According to another advantageous characteristic of the invention, the method consists in applying the end of the fibers to a grinding wheel according to the previously defined combined movement, then in moving and applying the fibers above a second grinding wheel the same combined movement .

• - la figure 1 représente une vue schématique du mouvement combiné entre les fibres et la meule.
• - la figure 2 représente une vue schématique d'un mode de réalisation du dispositif utilisé pour la mise en oeuvre du procédé.

Other characteristics and advantages of the invention, and in particular, the preferential speeds of rotation will appear on reading the detailed description which follows and with reference to the appended drawings given by way of non-limiting example and in which:

• - Figure 1 shows a schematic view of the combined movement between the fibers and the grinding wheel.
• - Figure 2 shows a schematic view of an embodiment of the device used for the implementation of the method.

The combined movement schematically shown in Figure 1 is composed of a rocking back and forth 14, 14 'of the fibers above the grinding wheel 10 on either side of a plane perpendicular to the grinding plane, said grinding wheel 10 being driven in rotation (N) around its axis 12, parallel to the grinding plane, accompanied simultaneously by a rotation (n) between the grinding wheel 10 and the fibers, substantially in the grinding plane, around an axis 13 substantially perpendicular thereto.

The grinding wheel 10 is rotated about its axis 12 according to a movement represented schematically by the arrows referenced N in the figures, using a shaft, partially shown.

The rotary drive shaft is, moreover and simultaneously, driven by a relative movement of rotation, with respect to the natural fibers, rotation represented by the arrows references n in the figures, around an axis 13 passing through l 'axis of rotation 12 of the grinding wheel 10 and located in the plane thereof, while being substantially perpendicular to the grinding plane. This second movement (n) causes rotation between the fibers and the grinding wheel 10, substantially in the grinding plane.

The end of the fibers is, moreover, applied to the grinding wheel 10 animated by the double movement previously described, according to a back and forth movement, between two extreme positions illustrated in 14 and 14 'in FIG. 1; this pendulum movement is carried out on either side of a longitudinal plane perpendicular to the mean plane of the end of the fibers.

The fibers thus applied to the pack can be joined by bundles according to any assembly or be previously arranged on the support of a toothbrush.

FIG. 2 shows a device used for implementing a variant of the method according to the present invention consisting in applying the ends of the fibers to the grinding wheel 10 for the first time according to the combined movement described above, then moving and apply the fibers over a second grinding wheel 20 in the same combined movement.

To this end, the device consists of two grinding wheels 10, 20, the drive shafts of which are coplanar. Each of these grinding wheels 10 and 20 is driven by the double movement described above, respectively represented by the arrows N and n.

Each grinding wheel rotates at a speed (N) comprised for a grinding wheel of approximately 20 cm in diameter between 1000 and 5000 revolutions per minute, and preferably at a speed of 2000 revolutions per minute, or at a tangential speed comprised between 1250 m by minute and 6250 m per minute while the rotation of each drive shaft of the grinding wheels around the axes 13 and 23 which are perpendicular to them is carried out at a speed (n) of between 50 and 250 revolutions per minute and preferably at a speed of 120 revolutions per minute.

The method of treating and obstructing the medullary canal of each fiber then consists, firstly, in applying the end of the fibers to the grinding wheel 10 in a pendulum movement between two extreme positions 14 and 14 ′, then in moving in a second step the fibers above the second grinding wheel 20 and to apply thereto, in a third step, the end of these in a pendulum movement between two extreme positions 24 and 24 ', the toothbrush then being removed from the grinding station, as shown by the reference arrow A in FIG. 2.

According to the invention, the duration of a rocking back and forth of the fibers above each grinding wheel corresponds substantially to the duration of a complete rotation between the fibers and the grinding wheel, in the grinding plane.

In an example of implementation of the method given by way of nonlimiting example, each of the three times previously defined may last approximately half a second.

The process which is the subject of the present invention is well suited to all fiber diameters, whether these are extra hard, hard, medium or flexible.

The implementation of the process causes friction which, without burning the keratin, causes it to penetrate into micro-particles in the medullary canal. There is, moreover, a phenomenon of torsion imprinted at the end of the fibers, this phenomenon changes the texture of the fibers which tends to tighten and makes the fibers more resistant to brushing. These two phenomena, friction and torsion, combined and synchronized, have the effect of blocking the end of the fibers and making it sealed against any penetration of foreign bodies.

The implementation of the method on the other hand has the advantage of rounding off the end of the fibers and thereby rendering them non-aggressive for the gums.

Of course, the present invention is not limited to the embodiment which has just been described, from which other forms and other embodiments may be provided, without thereby departing from the scope of the invention , it is possible, for example, to obtain a rotation between the fibers and the grinding wheel, in the grinding plane, by rotation of said fibers and no longer of the grinding wheel.

Claims (7)

1. Method of treating the free ends of natural bristles used for the making of tooth brushes of the type comprising the known steps consisting of applying the free ends of bristles to a wheel (10) according to a combined relative movement composed of a to-and-fro oscillation (14, 14') of the bristles above the wheel (10) on both sides of a plane perpendicular to the grinding plane and comprising a simultaneous rotation (n) between the wheel (10) and the bristles, about an axis (13) substantially perpendicular to the grinding plane, wherein:

- said combined movement further comprises the rotation (N) of the wheel (10) about its axis (12) disposed parallel to the grinding plane, and

- the period of to-and-fro oscillation of the bristles above the wheel (10) corresponds to the duration of one complete revolution between the bristles and the wheel in the grinding plane.

2. Method according to claim 1, characterised in that the rotation between the bristles and the wheel (10) about an axis substantially perpendicular to the grinding plane, is effected about an axis (13) passing through the rotational aixs (12) of the wheel and in the plane thereof.

3. Method according to one of claims 1 and 2, characterised in that it consists of applying the bristles to the wheel according to the combined relative movement once, then removing the ends of the natural bristles from the surface of the wheel (10), and in re-applying for a second time, the bristles thereto, according to the same combined relative movement.

4. Method according to one of claims 1 and 2, characterised in that it consists of applying the ends of the bristles to one wheel (10) according to the combined relative movement, then removing and applying the bristles to the top of a second wheel (20), according to the same combined relative movement.

5. Method according to one of claims 1 and 4, characterised in that each of the wheels (10, 20) turns at a peripheral speed between 1250 and 6250 metres per minute and preferably of 2500 metres per minute.

6. Method according to one of claims 1 and 5, characterised in that the relative rotation between the wheel (10) and the bristles, in the grinding plane, is effected at a speed between 50 and 250 revolutions per minute, and preferably of 120 revolutions per minute.

7. Tooth brush with natural bristles treated by a method according to one of claims 1 to 7.

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