WO2013056926A1

WO2013056926A1 - Cutting system for hair clippers

Info

Publication number: WO2013056926A1
Application number: PCT/EP2012/068143
Authority: WO
Inventors: Olivier Smal
Original assignee: Babyliss Faco S.A.
Priority date: 2011-10-17
Filing date: 2012-09-14
Publication date: 2013-04-25
Also published as: PL2768638T3; RU2014119191A; RU2598067C2; CN103042541B; CN103042541A; ES2583432T3; KR101945574B1; KR20140082818A; CN202540334U; EP2768638B1; EP2583798A1; EP2768638A1

Abstract

The present invention relates to a cutting system for hair clippers, said invention comprising a mobile blade and a fixed blade, characterised in that, during use, said mobile blade moves back and forth with force F, said mobile blade comprising N number of teeth of varying lengths (x) and (y) and presenting two lead angles α and β, the relationship between the two lengths and the lead angles being defined in the following manner: - the x/y ratio is within the range of 1.33 to 6; - the β/α ratio is within the range of 1.2 to 3.33; where - α is within the range of 9° to 15°; where β is within the range of 18° to 32°.

Description

CUTTING SYSTEM FOR CLIPPER

Object of the invention

The present invention relates to a cutting system for a hair clipper. It relates more particularly to a movable blade having a plurality of teeth of different height and angle of attack.

State of the art

[0002] Hair clippers are now as well used by hairdressers as by the general public. Lawnmowers for hairdressing professionals are nevertheless more powerful because they are either directly connected to the 230 V sector, or equipped with powerful batteries allowing the use of knives producing a quasi perpendicular cut of the hair. This type of mower has movable blades with deep (long) teeth that do not suffer any limitation in terms of the angle of attack of the hair because very powerful torques of force are available.

Mowers consumer are significantly less powerful and must reconcile the angle of attack of the hair (opening angle of the teeth), and therefore the mowing capacity and available power. This compromise is reflected in particular by the configuration of the teeth on the movable blade, whose geometric shape must be adjusted to this constraint. To obtain a good cutting capacity, one must open (enlarge) the angle of opening of the teeth but to keep a sufficient number of teeth, the hollows must be shallow which does not allow to cut a lot of hair in few time.

Moreover, manufacturers are currently seeking optimized manufacturing methods to be able to offer a product of lower cost to the general public. Among these methods, etching, or "etching" in English, has a considerable advantage provided that the blade to be treated is sufficiently thin. The method of "etching" is to print a layer of polymer or protective wax on a steel blade and then treat it with an acid to create recesses unprotected places. Unaffected areas will be the blade teeth.

We are therefore in the presence of two constraints, the first being the limited power of a mower "general public" and the second being the relatively limited thickness of the movable blade to be able to practice a chemical erosion ("etching") . By limited thickness, we mean a dimension less than mm, and preferably less than 0.5 mm.

The low blade thicknesses and the limited power thus impose not only an angle of attack of the rather large hair type "guillotine", but also a relatively short tooth because a fine tooth and long would tend to break because of the small thickness of the blade.

On the other hand, it is necessary to have a certain depth (length) of tooth to not hinder the ability to mow.

The problem of optimizing cutting systems of lawnmowers has been studied in the prior art. The documents FR 2 398 584, US 2006/0156549, GB 2 435 845 and DE 10 2009 035 232 A1 are particularly representative of this type of study, although they are not dedicated to the optimization of a data processing system. cutting a mower "general public" as we discuss in this patent application.

Goals of the invention

The present invention aims to provide an optimized cutting system for a mower "general public". This optimization concerns both the cutting performance with the handicap of a relatively limited power and the reduction in manufacturing cost by using a thin blade that can be manufactured by "etching".

More particularly, the present invention aims to establish a practicable geometry on thin blade for a mower "general public" and for a fashion particular of the invention, a relationship between the geometry of the teeth of the movable blade and the force available for mowing.

Main characteristic elements of the invention

The present invention discloses a cutting system for a hair clipper having a movable blade and a fixed blade, said movable blade moving, in use, in a back-and-forth movement with a force F, characterized in said movable blade has a number of teeth N of two different lengths (x) and (y) and having two angles of attack a and β, the relationship between the two lengths and the angles of attack being defined in the manner next:

the ratio x / y is between 1.33 and 6;

the ratio β / α is between 1.2 and 3.55;

with

- ranged between 9 ° and 15 °;

- β between 18 ° and 32 °.

Particular embodiments of the invention have at least one or a suitable combination of the following characteristics:

• Preferably the relationship between the two lengths and the angles of attack is:

the ratio x / y is between 1.5 and 3;

the ratio β / α is between 1.42 and 2.8;

with

- ranged between 10 ° and 14 °;

- β between 20 ° and 28 °.

the ratio x / y is between 1.54 and 2.6;

the ratio β / α is between 1.61 and 2.36;

with

- ranged between 11 ° and 13 °;

- β between 20 ° and 24 °.

· The variables (x, y) and α, β are adjusted in such a way that the number of teeth N on a given moving blade remains constant. • The length (x) is constant and the only variables are the length (y) and the angles a and β.

• Preferably the sum α + β is constant.

• Preferably (x) is between 2mm and 4mm, preferably between 2 and 3mm, and (y) is between 0.3mm and 2mm, preferably between 0.5 and 1.5mm.

Preferably F is less than 16 N and preferably less than 13 N

• The blades preferably have a thickness of less than 1 mm, preferably less than 0.8 mm, particularly preferably less than 0.6 mm. Brief description of the figures

Figures 1 and 2 show a plan view of a movable blade of the prior art provided for a mower of great power with a large tooth length.

Figures 3 and 4 show a plan view of a movable blade of the prior art provided for a mower "general public" with a shorter tooth length.

Figures 5 to 10 show plan views of a series of possible configurations of a movable blade portion according to the invention, where the parameters (y) have been varied between 0.5 and 1 , 8 mm, as well as a between 9 ° and 15 ° and β between 18 ° and 30 °. Other configurations were tested where, in addition to the previous parameters, the parameter (x) was varied. For reasons of economy of figures, however, they have not been represented.

Figure 11 shows the method of measuring the force exerted by the movable blade, in use, during its movement back and forth.

Figure 12 shows a detail view in 3 D of the head of the mower provided with the movable blade according to the invention.

Detailed description of the invention

The performance of a hair clipper depends on many factors that can be more limiting as the available power is low. Without pretending to be exhaustive, mention may be made of the geometry of the movable blade and the fixed blade, and in particular the length and the angles of opening of the teeth, the sharpening angles and the number of teeth, the lubrication facilitating the movement back and forth, and the speed of this movement, the pressure of the movable blade on the fixed blade, etc.

The optimization of the cutting system of a hair clipper is a multifactorial problem. The present patent application has deliberately chosen to approach this problem by one of its preponderant parameters, which is the geometry of the teeth on the moving blade. This geometry is conditioned by the opening angles combined with the length of the teeth.

The present invention does not take into account a possible adaptation of the geometry of the teeth of the fixed blade to the teeth of the movable blade. It is therefore considered that the fixed blade invariably has regular teeth of generally triangular shape and whose length slightly exceeds that of the movable blade to avoid possible injury to the scalp. Nevertheless the following discussion could also apply to the fixed blade.

In order to find the best compromise between the available force torque and the opening angle of the teeth, the tooth of the movable blade has been configured to obtain a fairly long tooth with a closed opening angle. It has a shape that is in a way the synthesis between the long, narrow teeth generally found on high-powered mowers (see Fig. 1) and the short teeth used until now on low-power "general-purpose" mowers ( see Figs 1 and 2).

The method of manufacturing the blades by etching allows only the realization of very thin blades with a very sharp profile. Nevertheless, in this case, the longer the tooth, the more fragile it is. To overcome this fragility, the tip of the tooth is cut and hollowed to obtain a double point with different angles (α, β - see Fig. 3, 4 and 5).

The variables studied in this patent application are the lengths x and y and the angles a and β (see figures). The influence of the sharpening angles of the moving and stationary blades has been deliberately ignored. We consider here simply that a Optimal sharpening has been practiced to focus on the other parameters mentioned above.

The force F exerted by the movable blade was measured with a dynamometer. The diagram of this measurement is shown in Figure 8.

Tests were carried out with mowers of different power which allowed to delimit the parameters F, x and y and the angles a and β. For values of a less than 9 ° and β values less than 18 °, the number of teeth N per unit length is relatively high if the x / y ratios are low, for example less than 1.33. This case is close to the blades provided for professional mowers and requires high power. In addition, the relatively long teeth need a relatively large blade thickness and go against the use of "etching" technology for this type of blade.

For values of a greater than 15 ° and values β greater than

32 °, the number of teeth N per unit length is relatively small if the x / y ratios are high, for example greater than 6. This case does not require a high power and allows the use of technology "etching For this type of blade. The mowing capacity of this type of blade is however relatively limited.

Between the two extremes described above, a whole series of configurations are of course possible. However, it has been determined experimentally that for a blade having a thickness of less than 0.6 mm, values of x greater than 5 mm, preferably greater than 4 mm, are difficult to practice for issues of fragility of the blade. Furthermore, the values of x less than 1 mm, preferably less than 2 mm, are not really useful in practice because they limit too much the cutting capacity.

As the objective of the present invention was to provide a blade for a mower "general public", we conducted the tests with lawnmowers of this type. These are not able to deliver forces on the moving blade exceeding about 20 N, they are generally even less than 15 N.

The most conclusive tests have been shown in the table below. They are merely illustrative, and in no way intended to limit the scope of the present invention. These tests nevertheless made it possible to delimit approximately the ranges of the lengths and ratios of the length of the teeth as well as the practicable angles on a relatively thin movable blade. The table below shows that a powerful mower can be obtained with a judicious combination of opening angles and tooth lengths, even for a force delivered to the blade of less than 16 N.

Test X (mm) Y (mm) x / y a ° β ° β / α F (N) Evaluation section

1 2 1.5 1.33 9 18 2 15 Satisfactory

2 2.5 1 2.5 13 25 1.92 15 good

3 3 0.5 6 15 32 2.13 15 Satisfactory

4 2 1.5 1.33 9 32 3.55 15 Satisfactory

5 3 0.5 6 15 18 1.2 15 Satisfactory

6 2.5 1.5 1.33 11 20 1.81 15 good

7 2.5 1 2.5 12 24 2 15 Very good

8 2.5 1 2.5 12 24 2 12 good

9 2,5 1 2,5 11 22 2 12 good

10 2,6 1,1 2,36 12 22 1,83 12 Very good

11 2,6 1,8 1,44 9 18 2 12 satisfactory

12 2.6 0.5 5.2 15 30 2 12 satisfactory

13 2,35 1,31 1,79 12,5 22 1,76 12 Very good

Claims

1. A cutting system for a hair clipper comprising a movable blade and a fixed blade, said movable blade moving, in use, in a reciprocating movement with a force F, characterized in that said movable blade has a number of teeth N of two different lengths (x) and (y) and having two angles of attack a and β, the relationship between the two lengths and the angles of attack being defined as follows:

the ratio x / y is between 1.33 and 6;

the ratio β / α is between 1.2 and 3.55;

with

- ranged between 9 ° and 15 °;

- β between 18 ° and 32 °.

2. Cutting system according to claim 1, characterized in that the relationship between the two lengths and the angles of attack is:

the ratio x / y is between 1.5 and 3;

the ratio β / α is between 1.42 and 2.8;

with

- ranged between 10 ° and 14 °;

- β between 20 ° and 28 °.

Cutting system according to claim 1 or 2, characterized in that the relationship between the two lengths and the angles of attack is:

the ratio x / y is between 1.54 and 2.6;

the ratio β / α is between 1.61 and 2.36;

with

- ranged between 11 ° and 13 °;

- β between 20 ° and 24 °.

4. Cutting system according to any one of the preceding claims, characterized in that the variables (x, y) and α, β are adjusted in such a way that the number of teeth N on a given moving blade remains constant.

5. Cutting system according to any one of the preceding claims, characterized in that the length (x) is constant and that the only variables are the length (y) and the angles a and β.

6. Cutting system according to any one of the preceding claims, characterized in that the sum α + β is constant.

7. cutting system according to any one of the preceding claims, characterized in that (x) is between 2mm and 4mm, preferably between 2 and 3mm, and (y) is between 0.3mm and 2mm, preferably between 0.5 and 1.5mm.

8. cutting system according to any one of the preceding claims, characterized in that said force F is less than 16 N.

9. cutting system according to any one of the preceding claims, characterized in that said force F is less than 13 N.

10. Cutting system according to any one of the preceding claims, characterized in that said blades have a thickness of less than 1 mm, preferably less than 0.8 mm, particularly preferably less than 0.6 mm.

11. Mower comprising a cutting system according to any one of the preceding claims.