BRUSH FOR APPLYING A COMPOSITION TO THE EYELASHES OR EYEBROWS

Abstract

A brush for applying a cosmetic composition (P) to the eyelashes and/or eyebrows, having a core, preferably made of plastics material, having a longitudinal axis (X), a plurality of rows of spikes disposed around the core and along the latter, where, for at least each of a number k of said rows, where k is greater than or equal to 2, at least three successive spikes in this row, of respective ranks p, p+1 and p+2, have elongation axes (Y) that make respective angles a.sub.p, a.sub.p+1 and a.sub.p+2 at their base with the longitudinal axis (X) of the core, where p is an integer between 1 and n−3, where n denotes the number of spikes in the row, at least two of the angles a.sub.p, a.sub.p+1 and a.sub.p+2 being different, at least one spike of the same rank p having a different orientation a.sub.p for at least two of these k rows.

Claims

1. A brush for applying a cosmetic composition to the eyelashes and/or eyebrows, having: a core having a longitudinal axis, a plurality of rows of spikes disposed around the core and along the latter, where, for at least each of a number k of said rows, where k is greater than or equal to 2, at least three successive spikes in this row, of respective ranks p, p+1 and p+2, have elongation axes that make respective angles a.sub.p, a.sub.p+1 and a.sub.p+2 at their base with the longitudinal axis of the core, where p is an integer between 1 and n−3, where n denotes the number of spikes in the row, at least two of the angles a.sub.p, a.sub.p+1 and a.sub.p+2 being different, at least one spike of the same rank p having a different orientation a.sub.p for at least two of these k rows.

2. The brush as claimed in claim 1, wherein, for at least two consecutive rows of spikes, at least a part of the spikes in one row crosses at least a part of the spikes in the other row, when the brush is viewed from the side, in a direction perpendicular to its longitudinal axis.

3. The brush as claimed in claim 1, wherein the distances between the peaks of at least three consecutive spikes in at least one row are different.

4. The brush as claimed in claim 1, wherein the rows are all parallel to the longitudinal axis of the core.

5. The brush as claimed in claim 1, wherein the angles a.sub.p, a.sub.p+1 and a.sub.p+2 are all different, for at least E(n/2) different values of p, E denoting the entire part, n denoting the number of spikes in the row.

6. The brush as claimed in claim 1, wherein, for at least two of the k rows, the number N.sub.f of spikes oriented toward the front and the number N.sub.r of spikes oriented toward the rear satisfies the relationship 0.3<N.sub.f/N.sub.r<2.5.

7. The brush as claimed in claim 1, wherein, for at least two of the k rows, the number of successive spikes that are all oriented either toward the front or toward the rear is less than or equal to 6 for this row.

8. The brush as claimed in claim 1, wherein the spacing at the base and/or at the peak of the spikes in at least two of the k rows is not constant.

9. The brush as claimed in claim 1, wherein, for at least two of the k rows, the number N.sub.f of spikes oriented toward the front and the number N.sub.r of spikes oriented toward the rear satisfies the relationship N.sub.f/N.sub.r>1.1 or N.sub.r/N.sub.f>1.1.

10. The brush as claimed in claim 1, wherein, when the brush is viewed from the side in a direction perpendicular to its longitudinal axis, at least a part of the spikes in one row crosses those in the adjacent row.

11. The brush as claimed in claim 1, wherein, when the brush is viewed from the side in a direction perpendicular to its longitudinal axis, at least a part of the spikes in one row does not cross any spike in the adjacent row.

12. The brush as claimed in claim 1, wherein the elongation axes of the spikes in at least two of the k rows are all contained in a single plane.

13. The brush as claimed in claim 1, wherein, for at least two of the k rows the length of the spikes in the row varies.

14. The brush as claimed in claim 1, wherein the longitudinal axis of the brush is rectilinear.

15. The brush as claimed in claim 1, wherein, for at least two of the k rows the number of pairs of consecutive spikes in which the two spikes are both oriented toward the front or are both oriented toward the rear is less than or equal to 50% of the total number of pairs of consecutive spikes in the row.

16. The brush as claimed in claim 1, wherein, for at least two of the k rows, the number of pairs of consecutive spikes in which the two spikes are oriented with opposite orientations toward the front and toward the rear, or vice versa, is less than or equal to 75% of the total number of pairs of consecutive spikes in the row.

17. The brush as claimed in claim 1, wherein, for at least two of the k rows, the number n of spikes in the row is greater than or equal to 10.

18. The brush as claimed in claim 1, wherein the number m of rows is between 6 and 20.

19. The brush as claimed in claim 1, wherein, with f being the total number of spikes of the brush and q the total number of values of different orientations a.sub.p,y, the ratio q/f is greater than or equal to 50%, p being the rank within the row and y the number of the row.

20. The brush as claimed in claim 1, wherein at least a part of the spikes have at least one edge.

21. The brush as claimed in claim 1, wherein all of the spikes in at least two of the k rows have a flat face contained in a single plane for the row.

22. The brush as claimed in claim 1, wherein, for at least two of the k rows, the distances between the peaks of consecutive spikes in one row are different for at least half of the pairs of consecutive spikes in this row.

23. The brush as claimed in claim 1, wherein, for at least two of the k rows, the distances d.sub.i and d.sub.i+1 between the peaks of three consecutive spikes of ranks i, i+1 and i+2 in a row satisfy d.sub.i< >d.sub.i+1.

24. The brush as claimed in claim 1, which has two rows of consecutive spikes with different configurations, the other rows of spikes being formed by the repetition of these two rows, with one alternating with the other around the longitudinal axis of the brush.

25. The brush as claimed in claim 1, wherein the number of pairs of consecutive spikes within one row that have a width that, for the first spike in the pair, increases with respect to the preceding one and, for the second spike in the pair, decreases with respect to the preceding one, or, for the first spike in the pair, decreases with respect to the preceding one and, for the second spike in the pair, increases with respect to the preceding one, is greater than or equal to ⅓ of the total number of spikes in the row and less than or equal to ⅘.

26. The brush as claimed in claim 1, wherein the orientations of the elongation axes of the spikes with respect to the longitudinal axis of the brush are between 70° and 110°.

27. The brush as claimed in claim 1, wherein the standard deviation between the orientations a.sub.p of the spikes within one row is between 5 and 15°.

28. A device for packaging and applying a cosmetic composition to the eyelashes and/or eyebrows, having: a container containing the composition to be applied, a brush as defined in claim 1.

29. A method for cosmetically treating the eyelashes and/or eyebrows, involving applying a cosmetic composition to the eyelashes and/or eyebrows with the aid of a brush as claimed in claim 1 or a device as claimed in claim 28.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The invention may be understood better from reading the following detailed description of a non-limiting implementation example thereof and from studying the appended drawing, in which:

[0051] FIG. 1 schematically shows, in partial longitudinal section, an example of a packaging and application device according to the invention,

[0052] FIG. 2 shows a side view of the brush, on its own,

[0053] FIG. 3 is a face-on view of the brush in FIG. 2,

[0054] FIG. 4 is a longitudinal section through the brush in FIG. 2,

[0055] FIG. 5 shows a detail of the implantation of the spikes,

[0056] FIG. 6 is a view of the implantation of the spikes on the brush, after the surface of the core has been flattened,

[0057] FIG. 7 is a perspective view of the brush,

[0058] FIG. 8 is a perspective view of a brush variant according to the invention,

[0059] FIG. 9 is a face-on view of the brush along IX in FIG. 8,

[0060] FIG. 10 is a longitudinal section through the brush in FIG. 8 in the plane of a row, and

[0061] FIG. 11 is a view, similar to FIG. 10, in the plane of a row consecutive to the one in that figure.

DETAILED DESCRIPTION

[0062] FIG. 1 illustrates a packaging and application device 1 having a container 3 containing a product P to be applied and an applicator 2 for applying the latter.

[0063] In this example, the container 3 has a neck 4 that receives a wiping member 6, in a manner known per se.

[0064] The applicator 2 has a gripping member 5, which also forms a closure cap for the container 3, and bears a stem 7, provided at its opposite end from the gripping member 5 with a brush 10 according to the invention, which is shown on its own in FIG. 2.

[0065] The wiping member 6 is for example a wiping member having an elastomer lip, the inside diameter of which corresponds to that of the stem.

[0066] The brush 10 is made of thermoplastic material, preferably by injection molding, but the invention is not limited to a particular material for producing the brush.

[0067] The brush 10 has a core 11, and spikes 12 that protrude from the core.

[0068] The core 11 is extended at one end by an end piece 13 for fixing the brush 10 in the stem 7.

[0069] The spikes 12 are organized on the brush 10 in rows 14, of which there are for example sixteen, as can be seen in FIG. 3.

[0070] All of the spikes 12 in an i.sup.th row 14 are oriented substantially on a single radial plane R.sub.i containing the longitudinal axis X of the brush 10, as illustrated in particular in FIG. 3.

[0071] Within this i.sup.th row 14, the spikes 12 are identified by their rank p from the proximal end 15 of the brush 10 and by the abscissa x.sub.p,i at their peak from a reference plane, as illustrated in FIG. 5.

[0072] The angle that the elongation axis Y of a spike 12 of rank p in one row i makes with respect to the longitudinal axis X of the core is denoted a.sub.p,i. This angle is measured at the base of the corresponding spike. Preferably, the elongation axis Y of a spike is rectilinear. The elongation axis Y of a spike 12 is the axis that passes through the centers of mass of its cross section, from the base at which the spike 12 is attached to the core to its peak. Where necessary, the angle a.sub.p,i is measured in projection in a plane that contains the longitudinal axis X of the core and the axis of the row, a value of 90° meaning that the elongation axis Y of the spike 12 is contained in a plane perpendicular to the longitudinal axis X of the core 11, a value less than 90° that the spike is oriented toward the proximal end of the core, that is to say toward the stem 7 that supports the brush 10 (i.e. toward the rear), and a value greater than 90° that the spike is oriented toward the distal end of the core (i.e. toward the front).

[0073] The width of a spike 12 of rank p in a row of order i at its base is denoted l.sub.p,i This width is measured parallel to the longitudinal axis X of the core.

[0074] In the example in question, the spikes 12 each have a semi-conical shape, with a flat face 22. All of the spikes 12 in one and the same i.sup.th row 14 have their flat faces contained in a single plane R.sub.i, which is preferably a radially oriented plane, as can be seen in FIG. 3.

[0075] It can be seen in FIGS. 4 and 5 in particular that, for at least two consecutive rows of spikes, at least a part of the spikes in one row crosses at least a part of the spikes in the other row, when the brush is viewed from the side, in a direction perpendicular to its longitudinal axis, as in these figures. Such crossings form grooves or Vs 20 in which the eyelashes can fit, and make possible in particular to spread the composition on the surface thereof.

[0076] The brush 10 for example has the following characteristics: for three successive rows 14 of spikes, x denotes the abscissa of the peak of the spike of rank p, a the inclination of its elongation axis Y with respect to the longitudinal axis X of the core at its base, and l the width at its base, measured in the direction of the longitudinal axis X. Since each spike 12 has a semicircular cross section, with a flat face contained in the corresponding radial plane R.sub.i, the width at the base of the spike also corresponds to the diameter of the spike at its base.

TABLE-US-00001 TABLE 1 Row Spikes x Angle a l Row 1 Spike 1 1.36 69.51 0.78 Spike 2 3.76 89.8 0.5 Spike 3 5.32 100.93 0.74 Spike 4 6.17 93.82 0.5 Spike 5 7.01 74.74 0.51 Spike 6 8.97 94.82 0.47 Spike 7 9.96 86.79 0.47 Spike 8 11.55 94.82 0.47 Spike 9 13.08 108.86 0.48 Spike 10 14.68 108.02 0.73 Spike 11 15.92 97.83 0.48 Spike 12 16.76 79.67 0.75 Spike 13 19.12 95.87 0.8 Spike 14 20.77 82.69 0.8 Spike 15 21.87 84.77 0.47 Spike 16 23.14 94.83 0.44 Spike 17 24.17 94.83 0.39 Spike 18 24.8 79.61 0.53 Row 2 Spike 1 0.6 73.82 0.51 Spike 2 1.97 95.02 0.5 Spike 3 2.96 86.99 0.5 Spike 4 4.55 95.02 0.5 Spike 5 6.08 109.06 0.49 Spike 6 7.68 108.21 0.73 Spike 7 8.45 84.98 0.5 Spike 8 9.92 93.03 0.47 Spike 9 10.76 79.86 0.7 Spike 10 13.12 96.08 0.72 Spike 11 14.77 82.89 0.77 Spike 12 15.22 71.8 0.71 Spike 13 17.44 81.97 0.5 Spike 14 18.37 84.97 0.53 Spike 15 19.94 95.02 0.54 Spike 16 21.82 101.13 0.69 Spike 17 22.34 81.96 0.45 Spike 18 23.62 96.09 0.58 Spike 19 24.62 101.16 0.52 Spike 20 25.04 81.95 0.38 Row 3 Spike 1 0.55 98.91 0.49 Spike 2 1.38 81.74 0.5 Spike 3 2.92 97.83 0.5 Spike 4 3.76 79.67 0.76 Spike 5 6.12 95.88 0.74 Spike 6 7.77 82.69 0.76 Spike 7 9.23 71.6 0.69 Spike 8 11.45 81.77 0.48 Spike 9 12.38 84.77 0.48 Spike 10 13.94 94.82 0.5 Spike 11 14.97 94.83 0.5 Spike 12 15.61 79.65 0.77 Spike 13 16.86 89.8 0.49 Spike 14 18.32 100.92 0.77 Spike 15 19.17 93.82 0.51 Spike 16 20.01 74.74 0.55 Spike 17 22.28 108.87 0.46 Spike 18 22.76 89.8 0.42 Spike 19 24.03 108.05 0.54 Spike 20 24.41 74.72 0.4
The values a, x and l are only given for three rows by way of example, and the values for the other rows are chosen so as to comply with one or more of the conditions given above, and thus have, in these remaining rows, the same characteristics as for the first three rows.
It will be noted on studying this table that, within one row of spikes 12 of a brush 10 according to the invention, spikes having orientations toward the rear (a<90°) and toward the front (a>90°) are found.
It can be seen that, for the three rows 14 in the above table, at least three successive spikes in each row, of respective ranks p, p+1 and p+2 and with peaks of abscissae x.sub.p, x.sub.p+1 and x.sub.p+2 along the longitudinal axis of the brush, have elongation axes Y that make respective angles a.sub.p, a.sub.p+1 and a.sub.p+2 with the longitudinal axis X at their base, where p is an integer between 1 and n−3, where n denotes the number of spikes in the row, where at least two of the angles a.sub.p, a.sub.p+1 and a.sub.p+2 are different.
In addition, at least one spike 12 of the same rank p has a different orientation a.sub.p from one row 14 to the next.
In addition, it can be seen that, for these rows, the number N.sub.f of spikes oriented toward the front and the number N.sub.r of spikes oriented toward the rear satisfy the relationship 0.3<N.sub.f/N.sub.r<2.5.
Thus, for row 1: N.sub.f=10 and N.sub.r=8, i.e. N.sub.f/N.sub.r=1.25, for row 2: N.sub.f=10 and N.sub.r=10, i.e. N.sub.f/N.sub.r=1, for row 3: N.sub.f=9 and N.sub.r=11, i.e. N.sub.f/N.sub.r=0.81.
It can also be seen that, for at least some rows, the number N.sub.f of spikes oriented toward the front and the number N.sub.r of spikes oriented toward the rear satisfy the relationship N.sub.f/N.sub.r>1.1 or N.sub.r/N.sub.f>1.1. In other words, the number of spikes oriented toward the front is different than the number of spikes oriented toward the rear, within one row.
In the example in question, the number of successive spikes 12 that are all oriented either toward the front or toward the rear is less than or equal to 6 for each of the rows. For example, the spikes of ranks 8 to 11 in the first row are all oriented toward the front, while the spikes of ranks 7 and 12 in this same row are oriented toward the rear.
Still in the example in question, the number of spikes oriented toward the front for which there exists a corresponding spike oriented toward the rear with the same angle in terms of absolute value is less than or equal to 1 for at least some rows. For example, this number is zero for the first row.
The number of spikes oriented perpendicularly to the longitudinal axis of the brush is zero for at least a part of the rows in the example in question, or even for all of the rows.
The number of pairs of consecutive spikes in which the two spikes are both oriented toward the front or are both oriented toward the rear may be less than or equal to 75% of the total number of pairs of consecutive spikes in the row, for at least some rows. Preferably, this proportion is greater than 25% and less than 50%.
For example, for the first row, which has 18 spikes and 17 pairs of consecutive spikes, only seven of them, which are formed by the pairs of spikes (1,2), (3,4), (8,9), (9,10), (10,11), (14,15), (16,17), concern spikes that are both oriented toward the front or toward the rear.
This results in a wide variety of orientations of the spikes on the brush.
The number of pairs of consecutive spikes in which the two spikes are oriented with opposite orientations toward the front and toward the rear, or vice versa, may be less than or equal to 75% of the total number of pairs of consecutive spikes in the row, for at least one row, and preferably each of the rows. Preferably, this proportion is greater than 25%.
For example, for the first row, the following pairs have two consecutive spikes with opposite orientations: (2,3), (4,5), (5,6), (6,7), (11,12), (12,13), (13,14), (15,16), (17,18), i.e. a ratio of 9/17=about 0.52. This is thus different than a fanned disposition of the spikes, which does not have such successions of spikes having opposite orientations.
It can also be seen in FIGS. 4 and 5, for example, that, for at least a part of the successive spikes of ranks i, i+1 and i+2 in the row, the distances between peaks of these spikes satisfy the relationship d.sub.i< >d.sub.i+1. Also, |x.sub.i+2−x.sub.i+1|< >| x.sub.i+1−x.sub.i|.
FIG. 6 shows the implantation of the spikes 12 on the core 11, and also their size.
It can be seen that, within at least one row 14, the size of the spikes varies, with, for example, for row 1, successions of three or four spikes with a small size less than or equal to 0.5 mm and a succession of three spikes with a large size greater than 0.5 mm, the spacings between the spikes also varying. For the first row, there are for example eight spikes with a large size, greater than 0.5 mm in diameter at their base, and ten spikes with a small size, less than or equal to 0.5 mm in diameter at their base. The spacing between the centers of the spikes, given by the difference between the abscissae of two consecutive spikes, varies for example from less than 1 mm for some pairs of consecutive spikes to more than 1 mm for others.
The deviations |x.sub.i+1−x.sub.i| between the abscissae of the peaks of the spikes, for i between 0 and n−1, where n is the number of spikes in the row, may vary around an average value of between 1.2 and 1.5 mm, for at least one row, and better still for all of the rows. This variation may take place around a median value of between 1.1 and 1.45 mm. The distribution of these deviations may have a positive coefficient of asymmetry with respect to the average, in particular greater than 0.5.
An embodiment variant of the brush 10 will now be described with reference to FIGS. 8 to 11.
According to this variant, the brush has two arrangements of rows that repeat identically around the longitudinal axis of the brush, alternately.
In this example, the brush has sixteen rows 14, and there are therefore eight rows R.sub.2i, where i is an integer ranging from 1 to 4, which have a first configuration, and eight other rows R.sub.2i+1, with integer i ranging from 0 to 3, which have a second configuration, different than the first, the rows R.sub.2i alternating with the rows R.sub.2i+1 around the longitudinal axis of the brush. FIG. 10 shows a row R.sub.2i and FIG. 11 shows a row R.sub.2i+1.
There are for example the following values, for each of these rows.

TABLE-US-00002 TABLE 2 Rank Spike Distance w.sub.i−1, i spike row Abscissa × Spike base from preceding (R.sub.2i+1) spike peak inclination width spike 1 1.8 mm 73.62 deg 0.26 mm 2 3.8 mm 86.79 deg 0.3 mm 0.89 3 4.5 mm 80 deg 0.17 mm 0.59 4 6.3 mm 100 deg 0.25 mm 0.31 5 7 mm 70 deg 0.3 mm 1.79 6 9.7 mm 84.78 deg 0.2 mm 1.37 7 11.2 mm 79.66 deg 0.3 mm 1.28 8 13.1 mm 95.88 deg 0.19 mm 0.54 9 15.45 mm 110 deg 0.3 mm 1.06 10 16.8 mm 90 deg 0.18 mm 1.99 11 18.3 mm 100 deg 0.26 mm 0.52 12 19.35 mm 80 deg 0.28 mm 1.59 13 21 mm 88 deg 0.17 mm 0.76 14 22 mm 79.65 deg 0.3 mm 0.98 15 24.2 mm 100 deg 0.22 mm 0.59 16 25 mm 90 deg 0.26 mm 0.85 17 25.5 mm 80 deg 0.17 mm 0.48 18 26.6 mm 90 deg 0.2 mm 0.32

TABLE-US-00003 TABLE 3 Rank Spike Distance w.sub.i−1, i spike row Abscissa × Spike base from preceding (R.sub.2i) spike peak inclination width spike 1 2.35 mm 69.8 deg 0.3 mm 2 5.3 mm 90 deg 0.19 mm 1.44 3 6 mm 75 deg 0.3 mm 0.98 4 8 mm 95 deg 0.3 mm 0.36 5 9 mm 94.02 deg 0.19 mm 0.56 6 10.5 mm 95.02 deg 0.24 mm 1.02 7 12.3 mm 109.07 deg 0.24 mm 0.57 8 13.4 mm 80 deg 0.35 mm 2.04 9 14.5 mm 86 deg 0.3 mm 0.13 10 16.2 mm 98.03 deg 0.19 mm 0.59 11 17.3 mm 79.84 deg 0.3 mm 1.55 12 19 mm 96.07 deg 0.19 mm 0.37 13 20 mm 80 deg 0.3 mm 1.34 14 22.2 mm 100 deg 0.19 mm 0.67 15 23.2 mm 90 deg 0.21 mm 1.12 16 24.6 mm 95 deg 0.27 mm 0.63 17 26.25 mm 115 deg 0.27 mm 0.49
The abscissa of the spikes corresponds to the distance between their peak and a single reference plane for all of the spikes.
The inclination of a spike corresponds to the angle between the elongation axis of the spike and the longitudinal axis of the core.
The distance from the preceding spike is expressed in mm and corresponds to the minimum gap measured along the longitudinal axis of the core between the spikes in question, at the base of the spikes by which they are attached to the core, as illustrated in FIGS. 10 and 11.
The width at the base of a spike corresponds to the width measured along the longitudinal axis of the core at the base of the spike by which it is attached to the core.
In this example, the spikes 12 have the same shape in section as those of the brush in FIG. 1. The width at the base of the spikes thus corresponds to the width of their flat side.
On studying the above values, it will be seen that each of these two rows has all or some of the following characteristics:

[0077] for each of the rows, more than four consecutive spikes are all oriented either toward the front or toward the rear,

[0078] there are at most three spikes perpendicular to the longitudinal axis of the core,

[0079] there are never two consecutive spikes perpendicular to the longitudinal axis of the core,

[0080] the number N.sub.f of spikes oriented toward the front is greater than that N.sub.r of the spikes oriented toward the rear for one of the rows, while the opposite is the case for the other row,

[0081] the number of changes in orientation of the spikes from the front to the rear or vice versa within one row is greater than or equal to ¼ of the total number of spikes in the row and less than or equal to ½,

[0082] the number of pairs of consecutive spikes within one row that have a width that, for the first spike in the pair, increases with respect to the preceding one and, for the second spike in the pair, decreases with respect to the preceding one (this being the case for example of the pair of spikes of ranks 2 and 3 in the row R.sub.2i+1), or, for the first spike in the pair, decreases with respect to the preceding one and, for the second spike in the pair, increases with respect to the preceding one, is greater than or equal to ⅓ of the total number of spikes in the row and less than or equal to ⅘,

[0083] the number of spikes at a time where two consecutive spikes are the same width may be less than or equal to 2, and it is possible for at least one of the rows not to have any spike that follows another with the same width,

[0084] the ratio between the number of spikes oriented toward the front and the total number of spikes within one row is between ¼ et ⅔, or even between ¼ and ½ or between ½ et ⅔ with respect to the total number of spikes in this row,

[0085] the ratio between the number of spikes oriented toward the rear and the total number of spikes within one row is between ⅓ and ⅔,

[0086] the orientations of the spikes are between 70° and 110°,

[0087] the widths of the spikes are between 0.15 and 0.35 mm, better still between 0.17 and 0.3 mm,

[0088] the gaps w between consecutive spikes at their base are between 0.1 and 1.8 mm, with an average of between 0.75 mm and 1.25 mm,

[0089] the number of times where one spike of the same rank has an opposite orientation to that of a spike of the same rank in the consecutive row is greater than or equal to ½ with respect to the total number of spikes in this row, and preferably less than or equal to ¾,

[0090] the number of times where one spike of the same rank has an orientation in the same direction, toward the front or toward the rear, as that of a spike of the same rank in the consecutive row is greater than or equal to ¼ with respect to the total number of spikes in this row, and preferably less than or equal to ½,

[0091] the average of the inclinations of the spikes within one row is between 80 and 100°, in particular between 90° and 100°,

[0092] the standard deviation between the orientations of the spikes within one row is between 5 and 15°,

[0093] the number N.sub.f of spikes oriented toward the front and the number N.sub.r of spikes oriented toward the rear satisfy the relationship 0.3<N.sub.f/N.sub.r<2.5, where preferably N.sub.f/N.sub.r is other than 1; in particular, for each of the rows, 0.4<N.sub.f/N.sub.r<⅕,

[0094] the number N.sub.f of spikes oriented toward the front and the number N.sub.r of spikes oriented toward the rear satisfy the relationship N.sub.f/N.sub.r>1.1 or N.sub.r/N.sub.f>1.1,

[0095] the length of the spikes in the row varies,

[0096] the number of pairs of consecutive spikes in which the two spikes are both oriented toward the front or are both oriented toward the rear is less than or equal to 50% of the total number of pairs of consecutive spikes in the row, and in particular is between 25 and 35%,

[0097] the number of pairs of consecutive spikes in which the two spikes are oriented with opposite orientations toward the front and toward the rear, or vice versa, is less than or equal to 75% of the total number of pairs of consecutive spikes in the row,

[0098] the number n of spikes in the row is between 15 and 25,

[0099] the distances between peaks of consecutive spikes in a row are different for at least half of the pairs of consecutive spikes in this row,

[0100] the distances d.sub.i and d.sub.i+1 between the peaks of three consecutive spikes with respective abscissae x.sub.i, x.sub.1+1 and x.sub.i+2 in the row satisfy d.sub.i< >d.sub.i+1.

Needless to say, the invention is not limited to the examples that have just been described. For example, the orientations of the spikes and the distribution of the sizes of the spikes, and their disposition, may vary within variants that are not illustrated.
The brush may be manufactured by a technique other than injection molding, and from a material other than a thermoplastic material, if necessary.
The spikes may be given a different shape, for example a conical or cylindrical shape or a shape with irregularities or protuberances.