JP5242559B2 - Bottom blade for electric razor shaving head - Google Patents

Abstract

The present invention relates to a lower cutter (4) for a shaving head, equipped with an upper cutter (7), of an electric razor, comprising at least one blade (10) which has a cutting edge (11) pointing in a direction of movement. The invention also relates to a shaving head having such a lower cutter and to an electric razor equipped with it. It is proposed to no longer give the cutting edge the conventional wedge-shaped configuration in which simply two planes inclined at an acute angle define the cutting edge contour. According to the invention, the cutting edge has, one behind the other in the direction of movement (16), at least two cutting edge sections (18,19) having different cutting angles. By means of a cutting angle graduation or a changing cutting angle, an optimum compromise can be achieved between the conflicting requirements of cutting behaviour and edge stability. The cutting edge section having the more obtuse or less acute cutting angle produces the desired cutting edge stability and at the same time provides for a long service life. On the other hand, the cutting edge sections having the more acute angle reduce the cutting forces, such that an improved threading behaviour can be achieved.

Description

  The invention relates to a lower blade with at least one blade having at least one blade oriented in at least one direction of movement for an electric razor shaving head with an upper blade. The present invention also relates to a shaving head having such a lower blade and an electric razor equipped with the shaving head.

An electric razor shaving head having such a lower blade is known, for example, from European Patent EP0743144B1 (Patent Document 1). According to this, the upper blade of the shaving head is formed as a perforated flake, below which the lower blade in the form of a blade block is reciprocated. In that case, the blade of the blade is sharpened and has a cutting angle of 35 ° to 90 °. German patent DE4423503C1 (patent document 2) also cooperates with a perforated blade plate, but for an electric razor shaving head whose blade edge has a cutting angle of 90 °, in contrast to the above-mentioned lower blade with a sharp edge. The lower blade is shown.
European Patent No. 0743144 German Patent Invention No. 4423503

  In known electric razors-regardless of whether they are formed in a rotating or reciprocating manner-the upper and lower blades always cooperate and they are at least partly in direct contact with each other. A razor with a lower blade having a so-called 90 ° cutting edge is characterized by being very gentle to the skin and has a high life with a high cutting edge stability. On the other hand, a lower blade having a blade sharpened at an acute angle is characterized by good passing behavior together with a small cutting force. In principle, it can be said that the smaller the cutting edge angle, the smaller the cutting force. However, small edge angles on the one hand cause problems associated with skin irritation when shaving, and on the other hand, as the edge angle decreases, the stability and life of the edge is increasingly impaired.

  Starting from this, the basis of the present invention is the problem of avoiding the disadvantages of the prior art and providing an improved lower blade and an improved shaving head and electric razor that brilliantly improve the prior art. is there. In particular, the present invention provides a lower blade having an excellent cutting behavior by a small cutting force and a good passing behavior without deteriorating the stability and life of the cutting edge.

  According to the invention, this problem is solved by a lower blade according to claim 1, a shaving head according to claim 23 and an electric razor according to claim 24. Preferred embodiments of the invention are the object of the dependent claims.

  It is therefore proposed that simply two planes inclined at an acute angle no longer give the blade a conventional wedge shape that defines the contour of the blade. According to the invention, the blade has at least two blade portions with different cutting angles, successively in the direction of movement. A step sequence of one or more cutting angles or varying cutting angles provides an optimal compromise between conflicting requirements of cutting behavior and cutting edge stability. A blade portion having a relatively dull or less sharp cutting angle will produce the desired blade stability and with it a long life. On the other hand, since the cutting force of the blade or blades having an acute cutting angle reduces the cutting force, the passing behavior can be improved and the energy consumption of the shaver can be reduced. Less.

  The first blade portion having a relatively blunt or less sharp cutting angle, especially when viewed in the direction of movement, is followed by at least one second blade portion having a sharper cutting angle. The incision into each eyelash is made by a less sharp blade part and can then be broken by a second blade part having a sharper cutting angle. This arrangement, preceded by a less sharp blade portion when cutting, is surprising or even inconsistent due to the challenge of obtaining a smaller cutting force. However, it has been found that the duller or less sharp blade part leading up greatly increases the stability of the blade and at the same time the cutting force can be lowered by the subsequent second (or even further) sharper blade part. did. A cutting angle that decreases in the direction of movement or cutting results in a very good compromise between stability and cutting behavior.

  Further developing the present invention, each blade portion is formed in a wedge shape with a generally flat wedge side. Accordingly, the blades are formed stepwise with respect to the cutting angle, the wedge side surfaces of each blade portion are flat, and each has a constant cutting angle. However, as an alternative, according to the present invention, at least one side of the wedge shape of the blade of the blade portion is given a convex or concave contour, and the cutting angle depends on which point the tangent of the cutting angle is taken. It is also possible to make a slight change inside the blade portion. However, when viewed as a whole, it is preferable that the geometrical relationship described above and below is satisfied with respect to the cutting angle of the blade portion.

  In order to obtain high stability on the one hand, but on the other hand to sufficiently reduce the cutting force, it is advantageous if the cutting angle of the first blade part is at least 10 ° greater than the cutting angle of the subsequent blade part.

  It is particularly advantageous to form a blade with a sharp edge as a whole and to arrange a plurality of successive blade portions with stepped cutting angles. In a further development of the invention, the blade portions each have a cutting angle of less than 90 °, in particular less than 65 °. It would in principle also be possible to give a right-angled profile to at least one blade part, in particular the preceding blade part during cutting. However, it is preferable to form all blade portions at an acute angle. This is because clearly improved cutting behavior and smaller cutting force can be obtained, and high stability can be maintained unless the cutting angle of the preceding blade portion is made too small.

  According to a preferred configuration of the invention, the preceding first blade portion can have a cutting angle of 45 ° ± 15 °, in particular about 45 °. The subsequent blade portion preferably has a cutting angle of 25 ° ± 5 °, in particular about 25 °.

  In principle, it is possible to evenly distribute the blade length to each blade portion as viewed in the direction of movement so that each blade portion has an equal length. However, it is preferred that each blade portion has a different length when viewed in the direction of movement or cutting direction.

  According to a preferred configuration of the invention, the blade is divided into two blade portions.

  In a preferred refinement of the invention, another blade part with a smaller cutting angle follows immediately after the first blade part, so that the first blade part just cuts the eyelashes and With a sharp blade, the blade bites into the eyelashes and eventually cuts it completely. In particular, the first blade portion is formed shorter than the usual diameter of eyelashes, usually 50 μm to 120 μm, when viewed in the direction of movement. According to a preferred configuration of the invention, the length of the first blade part in the direction of movement is less than 50 μm, in particular less than 25 μm. In a preferred refinement of the invention, the length of the first blade part is 1 μm to 20 μm, in particular about 5 μm.

  On the other hand, the length of the subsequent blade portion as viewed in the direction of movement can be greater than 20 μm, preferably greater than 50 μm. The total length can be 100 μm or more.

  In order to further develop the present invention and enable skin-friendly shaving regardless of the sharpness of the blade as a whole, the blade is inclined with respect to the blade upper surface facing the upper blade of the shaving head based on the specifications. In other words, since the upper surface of the blade is inclined downward, the original cutting edge is lower than most of the upper surface of the blade. It is preferable that at least the first blade portion is inclined in this way. However, a plurality of blade portions can be inclined. This lowering structure of the blade first further promotes the intended stability and life of the blade. This is because the inclined portion of the blade does not directly rub the upper blade, so that a reduction in wear can be obtained. On the other hand, this inclined structure of the blade is particularly advantageous for shaving that touches the skin. If the skin to be shaved protrudes into the shear hole of the upper blade, such skin protrusion is not immediately captured by the inclined blade edge, or such skin protrusion is again caused by the blade upper surface higher than the blade edge. It can be extruded from the shear hole of the upper blade.

The blade can in principle be tilted to various degrees. According to a preferred configuration of the invention, the blades are inclined at one or more inclination angles of about 0.5 ° to 45 °, in particular 1 ° to 20 °. In a preferred improvement of the invention, the blade can be inclined at about 5 °. In particular, α _{i + 1} <α _i (i = 1,..., N−1) with respect to the inclination angle. In particular, all inclination angles α _{1 to} α _n are in the range of 0.5 ° to 45 °.

  Further developing the invention, the difference between the highest point on the blade upper surface and the height of the cutting edge of the first blade part is about 1 μm to 20 μm, especially less than 10 μm.

  Depending on the functional principle of the shaving head, at least one lower blade can be formed as a double blade or a single blade. It is preferable to provide one blade for the rotary lower blade and two opposite blades for the reciprocating lower blade, and use one blade during forward movement and the opposite blade during backward movement.

  Of course, the lower blade can have a number of blades. In particular, the blades are arranged parallel to each other and are generally aligned substantially transverse to the direction of movement. The lower blade can be formed in the form of a blade block.

  If a reciprocating drive is provided for one or more lower blades, this can be formed in particular in a linear reciprocating type. However, as described above, it is of course possible to use this lower blade even with a shaving head or electric shaver provided with a rotary drive device for the lower blade.

  In an embodiment that can be manufactured particularly inexpensively, the lower blade is made of a sheet metal molded article, and at least one blade portion of the blade of the blade is manufactured in particular by an etching method. In an advantageous configuration of the invention, the lower blade (4) and / or at least the blade (11) is manufactured by electrochemical etching, coining, grinding, sintering or injection molding.

  It is particularly advantageous with regard to the life of the lower blade if the blade is at least partially provided with a wear protection layer.

  Other objects, features, advantages and potential applications of the present invention will be apparent from the description of the examples below. It should be noted that all the features described or illustrated can constitute the object of the present invention alone or in any combination and sub-combination irrespective of the gist of the invention described in the claims or the corresponding text of the claims.

  FIG. 1 shows the basic structure of an electric razor. The electric razor is used for accommodating, inter alia, an electric motor and, in some cases, a storage battery for energy storage, and comprises a case 1 with an operating switch 2. A reciprocating drive element 3 is led out from the case 1 on the upper end face. In the illustrated configuration, the lower blade 4 composed of two shearing elements 5 has a connecting pin 6. The connecting pin 6 can be engaged with the drive element 3 and can be locked in particular. In this way, the two shearing elements 5 arranged in parallel to each other can be driven to reciprocate in the longitudinal direction according to the double arrow 16.

  The lower blade 4 is at least partially surrounded or covered by the upper blade 7. The upper blade 7 includes an exchangeable frame that can be locked to the case 1 and a blade plate 9 fixed to the exchangeable frame 8. The blade plate 9 has a through-hole formed in one surface, and this through-hole can be formed as a hole or a slit, and the hair shaved during the shaving operation enters the shaving head through the through-hole. Based on the relative movement of the lower blade 4 relative to the upper blade 7 and the blade edge formed in the through hole of the blade plate and the shearing element 5 of the lower blade 4, the hair that has entered the shaving head is sheared between the blade edges. Disconnected.

  FIG. 2 shows an enlarged view of the shear element 5 of the lower blade 4 in which a number of blades 10 are arranged in parallel—in the configuration shown, in parallel with one another. As can be seen in FIG. 3, the blades 10 of the lower blade 4 are each formed in a U-shape, and are disposed on the opposite sides of the blades 10 at the free ends of the strip-shaped blades 10 bent in the U-shape. The blades 11 are arched and are opposite to each other. The strip-shaped fixing portions 12 aligned along the movement direction of the lower blade 4 can fix the shearing element 5 to the connecting piece, and can be connected to the driving device by the connecting piece.

  As shown in FIG. 4, the opposing blades 11 of each blade 10 are inclined downward with respect to the blade upper surface 13. In that case, the blade upper surface 13 passing between the two opposing blades 11 has a central raised portion 14. In the illustrated configuration, the central raised portion 14 is formed flat and defines a contact surface 0, and each blade 10 slides on the lower surface of the upper blade 7 along this contact surface. This central raised portion 14 is followed by an outer slope 15. The inclined surface 15 rises from the cutting edge 17 of the blade 11 to the central raised portion 14 at an inclination angle α to the upper surface of the blade, that is, upward in FIG. The inclination angle α is 0.5 ° to 30 °, in particular about 1 ° to 20 °, in particular about 5 °. The height difference shown in FIG. 4 between the raised portion 14 of the blade upper surface 13 and the cutting edge 17 is preferably 1 μm to 20 μm. If this is over-selected, there is a risk of drawing hair between the blade plate and the lower blade, so that this hair will not be cut and will only be tightened and / or torn. If selected too small, there will be a risk of skin irritation.

As shown in FIG. 4, the blade 11 of the blade 10 has a staged arrangement of cutting angles. Each of the first blade portions 18, which are respectively forward in the movement or cutting direction 16 and provided with a cutting edge 17, has a cutting angle φ ₁ of less than 90 °, in particular 45 ° ± 15 °. This cutting angle decreases backward along the blade as seen in the direction of motion. The second blade portion 19 that follows the first blade portion 18 at the time of cutting has a cutting angle φ ₂ of 25 ° ± 5 °, which is formed smaller than the cutting angle φ _{1 in} the preferred configuration of the present invention.

The first blade portion 18 that produces the incision extends in the direction of movement, in particular over a length ε ₁ (see FIG. 4) of less than 50 μm, and in a preferred embodiment of the invention 1 μm to 20 μm.

  In the illustrated configuration of FIG. 4, a step arrangement of cutting angles is provided on the lower surface of the blade 11 on the side opposite to the upper blade 7 based on the specification. In that case, in the illustrated embodiment, the two blade portions 18 and 19 are each formed in a wedge shape with flat wedge sides. That is exactly the blade profile of FIG. Of course, the wedge side surface is also curved in a U-shape due to the shape of the U-shaped blade as a whole, and has an arch shape. Due to the stepwise arrangement of the cutting angles between the two blade portions 18 and 19, a second cutting edge 20 is produced on the lower surface of the blade 11 (see FIG. 4).

  The cutting edge 17 of the blade 11 is preferably slightly rounded. In that case, the cutting edge radius R of the cutting edge 7 is preferably 2 μm or less, particularly preferably less than 1 μm.

  It is preferable that the entire length of the blade 11 extending over the edge 11 of the blade 11, that is, the wedge shape of the blade along the movement direction 16 is more than 50 μm, preferably 100 μm or more (see FIG. 4). This ensures that the wedge shape of the blades completely enters the hair and breaks it.

FIG. 5 also shows a cross-sectional view of the blade along the line BB in FIG. This embodiment has an auxiliary inclination angle α2 and another cutting angle φ3 compared to the configuration of FIG. For geometric data that match each other, the same reference numerals as in FIG. 4 will continue to be used for the description of FIG. The blade 10 which is also formed symmetrically with respect to the center line has a blade upper surface 13 which also has a raised central portion 14 but is inclined downwards at the edges K1 and K2. Although the blade top surface 13 is inclined by an angle alpha ₂ in the region of between the crest K2 and K1 to the contact surface 0, the inclination angle of the sections from crest K1 to the cutting edge 17 is inclined angle alpha with respect to the contact surface 0 I am inclined to down _one. In that case, α ₁ is larger than α ₂ . As compared with the embodiment in FIG. 4, opposite edge 11 of the blade 10 not only has a first and second blade portions 18 or 19 of length epsilon ₁ or epsilon _2, further lengths epsilon ₃ the 3 blade portions 21 are provided. The third edge portion 21 is formed by a wedge angle phi ₃ is provided a separate wedge angle phase sequence on the lower surface at ridge K3. In this case, ε ₁ > ε ₂ > ε ₃ is satisfied. By arranging the auxiliary inclination angle α and / or the cutting angle φ, the cutting behavior of the lower blade is optimally adapted to the necessary criteria-the stability of the cutting edge on the one hand and the cutting force produced on the other hand. It should be noted that the number of cutting angles φ and / or inclination angles α used is not limited to the number 2 or 3 as described in the embodiment, and can be arbitrarily selected as long as at least two cutting angles are formed. Let's leave.

The perspective exploded view of an electric razor is shown. Fig. 4 shows a side view of the individual blade elements of the lower blade according to the invention of an electric razor shaving head according to an embodiment of the invention. FIG. 3 shows a cross-sectional view of the blade element of FIG. 2 along the line AA described in FIG. 2. FIG. 3 shows a cross-sectional view of the lower blade, taken along line B-B in FIG. 3. 4 shows another embodiment of a blade according to the invention.

Claims (25)

Lower blade with at least one blade (10) with at least one blade (11) facing at least one direction of movement (16) for an electric razor shaving head with upper blade (7) in the blade (11) is at least two Successive approximation to the motion direction, the cutting angle _{(φ 1, φ 2, φ} 3, ... φ n) possess different blade portions (18, 19, 20) of,
In the direction of motion (16), a first blade portion (18) having a _first cutting angle (φ ₁ ) has a second blade portion (19) having a _second smaller cutting angle (φ ₂ ). Continued,
The lower blade, wherein the blade (11) is formed to be inclined downward with respect to the blade upper surface (13) facing the upper blade (7) based on the specification . 2. The lower blade according to claim 1 , wherein another cutting angle φ _n follows the second blade portion (19), and φ _n <φ _n−1 for all angles φ. Lower blade according to claim 2 , characterized in that the preceding cutting angle (φ _n-1 ) is at least 10 ° greater than the subsequent cutting angle (φ _n ). Cutting angle of the blade portion (18, 19, 20) (phi ₁ to phi _n) is according to any one of claims 1 to 3, characterized in that formed at 90 ° less than the respective Lower blade. 5. The lower blade according to claim 1, wherein the first cutting angle is 45 ° ± 15 ° and / or the second cutting angle is 25 ° ± 5 °. Edge portion (18, 19, 20), each longitudinal section (B-B) at a flat, 1 to claim, characterized in that it is formed in approximately wedge-shaped in convex or concave wedge sides The lower blade according to claim 5 . The blade part (18, 19, 20) has a different length (ε ₁ , ε ₂ ,... Ε _n ) when viewed in the direction of movement (16), according to any one of the preceding claims. The lower blade described in one. The first edge portion (18) of any one of claims 1 to 7, characterized in that it has a length of 50μm less than the movement direction (16) to (epsilon ₁₎ in the direction of movement (16) Lower blade described in. 9. The lower blade according to claim 8 , wherein the length (ε1) of the first blade portion (18) is about 5 μm. All edge portion _{(ε 1, ε 2, ...} ε n) lower blade according to any one of claims 1 to 9 total length of the direction of movement of (16) is equal to or larger heard than 50μm . Lower blade of claim 1 blade (11), characterized in that the inclined downward at an inclination angle of more than by relative blade top (13) (alpha). The lower blade according to claim 11 , wherein α _{i + 1} <α (i = 1,... N−1). The lower blade according to claim 12 , wherein all the inclination angles α ₁ -α _n are in a range of 0.5 ° to 45 °. Any one of claims 12 or claim 13 the difference of the cutting edge (17) of between Noto height of the highest point of the blade top and blade (11) (D) is characterized in that it is a 1μm to 20μm Lower blade described in. 15. A lower blade according to any one of claims 1 to 14 , characterized in that the blade (10) has two opposing blades (11). The lower blade according to any one of claims 1 to 15, wherein a plurality of blades (10) are provided and arranged parallel to each other. The lower blade (4) according to any one of claims 1 to 16 , wherein the lower blade (4) comprises a sheet metal molded product. The lower blade according to any one of claims 1 to 17 , wherein the lower blade (4) and / or at least the blade (11) is manufactured by etching. Lower blade (4) and / or at least the blade (11) is an electrochemical etching, coining, grinding, any of claims 1 to 18, characterized in that it is manufactured by sintering, electroplating or injection molding The lower blade as described in one. 20. A lower blade according to any one of the preceding claims , characterized in that the blade (10) is at least partly provided with a wear protection layer. A shaving head for an electric razor comprising at least one lower blade (4) according to any one of claims 1 to 20 . An electric razor comprising the shaving head according to claim 21 . The electric shaver according to claim 22 , wherein the lower blade (4) is driven to rotate. The electric shaver according to any one of claims 22 and 23 , wherein the lower blade (4) is driven to reciprocate. 23. The electric razor according to claim 22 , wherein the lower blade (4) is driven to reciprocate linearly.

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