DE2723728A1 - GRID FOR THE CUTTER HEAD OF ELECTRIC SHAVERS AND SHAVERS FITTED WITH SUCH GRID - Google Patents

Description

Grids for the cutting head of electric razors and razors provided with such a grille.

The subject of the invention is a grille for the cutting head of an electric shaver.

Numerous electric razors are known whose cutting head is covered by a perforated grid. the Perforations of the grid work with cutting means, such as a row of knives, a comb or a second, arranged under the first grid perforated grating, which a reciprocating translational movement e.g. by means of an induction coil or an electric motor.

The perforations formed in such a grid allow the hair to be shaved to pass through and allow relative movement the cutting means causes this hair to be cut off.

Experience has shown that the quality and efficiency of the cut with such a perforated grid equipped razor to a large extent from the training of this Depend on the grid.

Much work has therefore been done to improve such a perforated grid.

British patent specification 468 545, for example, describes a razor head which is formed by a perforated grid and cutting means which can perform a translational movement relative to the grid. This patent indicates that the The cutting edges of the perforations of the grid are not parallel to those of the cutting means. Thanks to this arrangement, the hair is in the between the edges of the perforations of the grille and the edges of it

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Cutting means formed angle taken so that the hair like scissors be cut off. Such an arrangement is obtained e.g. if the perforations of the grid are circular, elliptical, oval or polygonal, while the edges of the cutting means are straight could be.

In the American patent Hr. 2,573,758 also describes a razor with a grid, the Perforations have the shape of rhombuses with rounded corners, W3l.:he are distributed on the grid in such a way that ridges with parallel edges arise between adjacent rhombi, and that the large diagonal the diamond is parallel to the straight edges of the knives below.

In the German patent specification Kr. 833 464 and the French patent specification No. 1 265 606 there is a grille for razors described which honeycomb-like distributed hexagonal has holes.

The advantage of providing the grid with hexagonal holes is that you get the best possible opening ratio of the grid according to a geometric property known for honeycomb-like structures, which is industrial has been used for the production of perforated partition plates, as shown in French patent specification No. 974 649.

French Patent No. 1,265,606 teaches that a good shave can be obtained when one of the large Diagonals of each hexagon of the grid at least approximately to the direction of movement of the cutting means arranged under the grid is parallel, which is already provided in one of the design modifications of German Patent No. 833 464 Perform relative movement.

This characteristic is technically complete in reality from the hexagonal outline of the perforations independent and is solely due to the scissor action taught by the aforementioned British Patent No. 468,545 which in detail the SehneidVorgang according to this Scissor action explained. The hexagonal shape of the perforations therefore does not play a specific role for the cut compared to another, the polygonal shape ensuring the scissor effect. For this reason, the most diverse forms have been provided, as is the case with

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called British patent or Fig. 7 of the American U.S. Patent No. 2,824,367 shows. The choice of hexagonal Perforations therefore ultimately only offer one advantage due to the above-mentioned known property of honeycomb-like structures.

Furthermore, the condition established by French patent specification No. 1,265,606 is to achieve the scissor effect not decisive, because if the edge of the cutting means has a sharp Yf rake and not a right angle with the direction of movement forms, the scissor effect is reduced and can even disappear completely if this angle is 60 °.

The real condition for achieving the scissor action with a grid with hexagonal holes is that the edge of the cutting means is perpendicular to one of the large diagonals of the hexagon, and this condition is found in the aforementioned American patent specification No. 2,573,758.

The applicant has also found that the grating described in French patent specification No. 1,265,606 with hexagonal holes has numerous disadvantages in practice.

Since NaEM I l, the large diagonal of the hexagon to the movement of the cutting means are parallel, the cutting of a hair within a hexagon only a maximum cutting length is possible, which corresponds to the height of the triangle formed by two adjacent sides of the hexagon. This amount is low. It is only half of one side of the hexagon. This considerably limits the efficiency of the cut. The hair lying within a hexagon outside the zone delimited by the base of the triangle formed by two adjacent sides of the hexagon can be cut off by moving the grille of the razor in the direction of movement of the cutting means. In the case of the ITr. 1 265 606, however, this displacement is relatively large (it takes place along a large diagonal of the rectangle), so that it is impossible to obtain the most favorable cutting quality.

The applicant has also found that the fact that on the grid is parallel to the direction of movement of the cutting means Arranging rows of hexagonal holes, for which the strength of the grid is extremely unfavorable. In this case there are

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borrowed the narrow connecting bridges between the rows of hexagons in an alignment parallel to the dumbbell lines of the cylinder surface, according to which the grid is bent on the head of the razor, so that there is a risk that the grid at the point of these connections bent in an irreversible manner or even broken when it experiences deformations along these surface lines.

In order to avoid such a risk of breakage, it is proposed have been to use relatively thick grids, which is obviously unfavorable for the quality of the shave.

It has also been proposed to make the design so that the direction of the rows of hexagons, the centers of which are in alignment, forms a certain angle with the direction of movement of the associated cutting means. In this way, the lines of the center points of the hexagons are no longer parallel to the sides of the grid, which leads to certain manufacturing difficulties, can create a loss of usable area and creates asymmetrical cutting conditions for the hair, which thus show a greater tendency to escape, so that some of the advantages derived from the seer effect are lost.

The invention aims to overcome the disadvantages of the grilles of razors with the aforesaid hexagonal holes to remedy a grid, which has an increased strength against the deformations, which it in use with the Movements on the skin of the user can be subjected, the grid also having an efficiency and a shaving effect allowed to obtain, which is at least comparable to that of the grids mentioned above.

In the grille for razors according to the invention, the hexagonal holes are arranged in rows, their centers lie in alignment, and the line of the midpoints forms a certain angle with the direction of movement of the movable ones Cutting means.

According to the invention, this grid is characterized in that one of the symmetry lines of each hexagon is parallel to the edge of the movable cutting means, so that the symmetry lines perpendicular to these lines of symmetry for the hexagons and the same row are offset from each other by a constant distance.

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In spite of the inclined position of the rows of hexagons in relation to the direction of movement of the movable visual cutting means, this is the position of the hexagons is most favorable compared to the edge of this cutting means.

This also avoids any risk of breakage of the grille when it is deformed along lines which are parallel to the direction of movement of the cutting means or the generatrix of the cylinder surface according to which the grille is bent on the head of the razor, the effectiveness and the Efficiency of the cut can be maintained under the most favorable conditions.

According to an expedient embodiment of the invention, the line of symmetry parallel to the edge of the movable cutting means is the line of symmetry the line connecting the center of two opposite sides of each hexagon.

This version corresponds to that in the French Patent specification No. 1 265 606 described, but with the essential difference that in the grating according to the invention, the large Diagonals of the hexagons remain in a direction parallel to the direction of movement of the movable cutting means, rather than with to form a certain angle in this direction in order to avoid the disadvantages mentioned above.

According to a preferred embodiment of the invention, the line of symmetry parallel to the edge of the movable cutting means is the line of symmetry one of the major diagonals of any hexagon.

The opposite edges of each hexagon are thus perpendicular to the direction of movement of the movable ones Cutting means.

The notifying party has found that this situation is still the improvement of the effectiveness and the efficiency of the cut compared to the previous embodiment allowed.

In either of the above two versions, the displacement between the to the to the edge is the movable Cutting means parallel lines of symmetry, vertical lines of symmetry, preferably selected so that the angle between the line of the center points of the hexagons of one and the same row and the direction of movement of the movable cutting means less than about 10 ° or is approximately equal to 10 °.

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For an angle greater than about 10, the ratio (open surface / total surface) of the grid is generally too small, so that part of the by the hexagonal shape the holes achieved is lost again.

Up to an angle of 10, on the other hand, it can be assumed that the inclination of the rows of hexagons in relation to the direction of movement the cutting means has practically no effect on the ratio (open surface / total surface) of the grid.

The smallest angle that exists between the rows of hexagons and the direction of movement of the cutting means must be cannot be precisely determined. However, one can assume that it must be greater than that corresponding to the tolerance with which the grille is fitted onto the head of the razor got to.

The invention is explained below by way of example with reference to the drawing.

Fig. 1 is a side view of the head of a razor equipped with a grille according to the invention below Breaking away of parts.

Fig. 2 is a section along the plane II-II of Fig. 1.

Figure 3 is a fragmentary top plan view of the preferred grille for razors of the present invention on a large scale Scale.

Figure 4 is a fragmentary top plan view of another large scale razor grille according to the present invention.

Fig. 5 is a view corresponding to the view of Fig. 2, showing that experienced by the grid during shaving Shows deformation.

Fig. 6 is a view corresponding to Figs. 3 and 4 showing, for comparison, a prior art grating shows.

FIG. 7 is a schematic view taken from FIG.

large hatred rod shows a hexagonal hole of the grid corresponding to FIG. 3 and a hair inserted into this hole.

FIG. 8 is a schematic view corresponding to FIG. 7, but which relates to the grid of FIG. 4.

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In the embodiment of FIGS. 1 and 2, the electrical A razor in a manner known per se has a head 1, which is supported by a perforated grating which is curved according to a cylindrical surface 2 is covered from metal. Below this grid 2 cutting means are arranged, which are formed by a comb 3, which one parallel to the direction of the longitudinal edges of the grating 2 reciprocating translational movement can be given »which e.g. by means of an induction coil or an electric motor (not shown) housed in the shaver · »; will. The comb 3 has teeth 3a, the upper one of which is circular arc-shaped End passes close to the grid 2, and which cooperate with the holes 4 formed in the grid 2 to the whiskers to cut off.

In Fig. 3 it can be seen that the holes 4 of the grid 2 are delimited by regular hexagons, which are distributed honeycomb-shaped and connected to one another by metallic webs 5 of constant thickness e. The hexagonal holes 4 are arranged in rows, the center points 0 of which are in alignment in a direction L which forms an angle 1 with the direction of movement of the camra 3.

According to the invention, in the example in FIG. 3 line of symmetry M formed by one of the large diagonals of each hexagon 4 parallel to the edge of the teeth 3a of the comb 3. The to the large diagonals M perpendicular lines of symmetry N are so for the hexagons 4 one and the same row against each other by one constant distance d offset. This shift between the hexagons 4 has the production of connecting webs 5 in parallelograrnmform result.

Correspondingly, the large diagonals M of the hexagonal holes 4 are perpendicular to the direction of movement D of the comb 3 and to the edges 2a of the grid 2.

In the example of FIG. 3, the distance a between two opposite sides of the hexagonal holes is 4 0.56 mm and the width of the metallic webs 5 between the Holes 4 0.21 mm. The thickness of the grid 2 is perforated in its Section 0.06mm, and the grid is made of nickel.

In the embodiment of FIG. 4, the line of symmetry is 1Γ, which passes through the center of the opposite side

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th line connecting each hexagon 4a is formed »parallel to the edge of the teeth 3a of the comb 3 · those to these lines N perpendicular large diagonals M are therefore for the hexagons 4a of one and the same row against each other by a constant distance d .. offset. As in the example of FIG. 3, the displacement between the hexagons 4a has the formation of connecting webs 5a in FIG Result in parallelogram shape.

In the embodiment of FIG. 4, the large 3n are also diagonals M of the hexagons 4a to the direction D- of the movement of the Crest 3 and parallel to the edges 2b of the grid (instead of perpendicular as in Fig. 3).

As a result of the displacement between the hexagons 4a, the line L .. forms the center points 0 of the hexagons 4a one and the same Row with the direction of movement D. of the teeth 3a of the comb an angle i., which in this example as in that of Fig. is about 10 °.

The fact that the grids shown in Fig. 3 and 4 have hexagonal rows 4 or 4a, which are offset from one another and thus inclined to the direction of movement D or D. of the comb 3, enables the considerable increase in the strength of these grids against deformations, which they can be exposed.

When the grid 2 is pressed against the skin to be shaved, the force F exerted on the grid 2 (see FIG. 5) deforms it and produces a bend 8 extending along a dumbbell line of the cylindrical surface formed by the grid 2.

In the case of a grid with hexagonal holes, which are directed in the direction of movement of the cutting means, which are parallel is to the surface lines of the cylindrical grid, such a kink 8 permanent kinks or breaks at the point of cause metallic ridges between the rows of hexagons.

In the grids shown in FIGS. 3 and 4, such dangers are avoided in that the hexagonal rows 4 or 4a form _{an angle i or I 1} with the movement direction D or D. of the comb3 3 and with the surface lines of the cylindrical surface formed by the grid.

Since the risk of breakage of the grid is avoided in this way

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a grid with a relatively small thickness of 0.06 mm can be used in the example given, so that it is very is flexible and conforms to very pronounced protrusions on the skin and so can produce a very close shave.

If the inclination i or i, the direction L or L. of the rows of hexagons 4 or 4a with respect to the direction D or D _{1 is kept} at an angle which is less than 10 ° or equal to 10 ° , it is found that the ratio between the open area (those of hexagons 4 or 4a) and the total area of the grid experience only a very small decrease compared to the most favorable ratio which is obtained when the rows of hexagons are in alignment with the direction D or D.

This decrease is, for example, of the order of 3 % if the angle 1 or i. is equal to 10 °. Such a decrease in the ratio between the open areas and the total area of the grating 2 has no effect on the efficiency and effectiveness of the cut.

Furthermore, thanks to the displacement of the hexagons 4 or 4a of one and the same row, the angle ί or i .. between the direction L or L _{1 of} the hexagonal rows and the direction of movement of the comb 3 has no effect on the effectiveness of the cut. The position of the hexagons 4 or 4a relative to the direction of movement D or D _{1 of} the comb 3 remains the most favorable, ie the large diagonals M of the hexagons 4 or the lines of symmetry N of the hexagons 4a remain exactly parallel to the edges of the teeth 3a of the movable comb 3 .

This is the case with the one described in French patent specification No. 1 265 606 and shown in FIG. 6 for comparison Grid not the case.

In this grid, the large diagonals M of the hexagons 4b of one and the same row are aligned with the direction L _{2 of} the center points 0 of the hexagons 4b.

If one therefore inclines the direction L2 of the hexagonal rows 4b with respect to the direction of movement D _{2 of} the teeth 3a or the direction of the edges 2 £ by an angle i «, the cutting angles formed at the ends of the diagonals M become asymmetrical with respect to the direction D-, which leads to leads to a significant reduction in the effectiveness of the cut.

It should also be noted that in the embodiment of FIG

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the connecting webs 5b_ rectangles separating the hexagons 4b instead Parallelograms are as in the grids according to the invention shown in FIGS. 3 and 4.

The grids according to the invention shown in FIGS. 3 and 4 therefore have the advantage that they relate to the direction of their bands 2a or 2b to withstand parallel deformations without the means used to achieve this object reducing the Effectiveness of the cut result, as in the case of the one in deii French patent specification No. 1 265 606 is the case.

In addition to this essential advantage, the one shown in FIG. 3 The grids shown have specific advantages over the grid of FIG. 4. In the grid of FIG. 4, the cutting edges E-F and G-F make an acute angle with the edges of the teeth 3a of the comb (see Fig. 8). In this grid, therefore, occurs in the American Patent specification Kr. 2,573,738 as well as in the grating described in French patent specification No. 1,265,606 Scissor action on.

However, such a scissor action does not exist a priori in the case of the grid shown in FIG Cutting edges A-B and C-D to the edge of the teeth 3a of the comb are parallel (see Fig. 7). One could therefore fear that the The grid of FIG. 3 is less effective than the grid of FIG. 4.

However, the applicant has the surprising finding made that all sides of the hexagons 4 including the sides A-B and C-D parallel to the edge of the teeth 3a of the comb 3 Hair like the hair 6 introduced into the hexagon 4 of FIG. 7 could be cut by the translational movement D of the comb 3.

The cutting length obtained for each hexagon 4 thus extends over a greatest distance N, which is equal to half of the distance between two opposite sides A-B and C-D.

In the embodiment of FIG. 4, however, the cut made for each hexagon 4a (see FIG. 8) extends over a distance N ₂ , which at best is equal to the height of the triangle EFG formed by two adjacent sides. This distance N ₂ is only equal to half of a side.

The grid shown in Fig. 3 therefore enables a

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NEN Sehneidwirkungsgrad better than 4 to obtain the Fig., this efficiency than that of the grating is erstrecht beseer according to French Pat. No. 1,265,606 due to the aforementioned asymmetry of the Sehneidwinkel.

Furthermore, when comparing FIGS. 7 and 8, one sees that, for cutting off de3, the hair 7 lying in the center of a hexagon is the Grid has to be shifted by a distance which is equal to N in the case of FIG. 7 and N in the case of FIG.

The distance N. (case of the grid of FIG. 3) is considerable smaller than the distance N. * (case of the 3 grid of Fig. 4).

This difference between the distances N ₁ and N gives an explanation for the fact that in the grid of FIG. 3 such a hair 7 is cut off more smoothly than in the embodiment of FIG.

This advantage of the grid shown in Fig. 3 is also specific to that in the French patent No. 1,265,606 described grating.

The training provided for the grid according to FIG. 3 therefore proves to be favorable, although it is not the case with the grid according to FIG. 4 or in the French patent specification No. 1 265 occurring scissors action.

The invention can of course be modified. So the comb 3 can be replaced by other movable cutting means, e.g. a second grid with perforations, the edges of which with the hexagonal holes of the grid according to the invention for cutting off the Hair work together.

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Claims (4)

Characters: dPatentanwälte_19Oipl-Ing. G. LeiserSDr. G. HauserPErnsbergerstrasse8 Munich 60 • Or / PrankreichR ü σDipt-mg. E. Prinz 2919H EATENTANSPSEB S.A. SELONGEY. CoteUnser 2723723 May 24, 1977 1. Grille for razors with hexagonal holes to interact with the edges of the movable, opposite cutting means translating said grid, said hexagonal holes being arranged in rows, their centers lie in alignment, the line of the midpoints making a certain angle with the direction of movement of the movable ones Forms cutting means, characterized in that one of the lines of symmetry (M, N) of each hexagon (4, 4a) is parallel to the Band of the movable cutting means (3a) is so that the lines of symmetry (M or N) perpendicular lines of symmetry for the hexagons of one and the same row (L or L) against each other by a constant Distance (d, d,) are offset. 2. Grid for razors according to claim 1, characterized characterized in that the line of symmetry (N) parallel to the edge of the movable cutting means (3a) is the center of two connecting opposite sides of each hexagon (4a) Line is. 3. Grid shaver according to claim 1, characterized in that to the edge of the movable Schneld- eittel (3a) parallel to the line of symmetry (M) one of the major diagonal of each hexagon (4). 4. Grid for razors according to one of claims 1 to 3 »characterized in that the displacement between the lines of symmetry (M) perpendicular to the lines of symmetry (M) perpendicular to the edge of the movable cutting means (3a) is chosen so that the angle (i) between the line of the centers of the hexagons of one and the same row and the direction of movement (D) of the movable cutting means (3a) less than about 10 ° or about the same 10 ° is. 809808/0592 ORIGINAL INSPECTED