Blade, Shaver With A Blade And Method For Producing A Blade

Abstract

An elongated outer blade for a slit cutter is disclosed. The outer blade extends along a first axis and comprises a number of slits and webs disposed between the slits. The webs have an upper surface, a lower surface and side surfaces extending between the upper and lower surfaces. At least some of the webs are provided with a concave clearance formed between a side surface and the lower surface forming an edge with the side surface. Further, a shaver having such an outer blade and a method for producing an outer blade using etching are disclosed.

Claims

1. An elongated outer blade for a slit cutter, the outer blade extending along a first axis and comprising a number of slits and webs disposed between the slits, wherein the webs have an upper surface, a lower surface and side surfaces extending between the upper and lower surfaces, wherein at least some of the webs are provided with a concave clearance formed between a side surface and the lower surface forming an edge with the side surface.

2. The blade according to claim 1, wherein the clearance forms an obtuse angle with the side surface and/or with the lower surface.

3. The blade according to claim 1, wherein a central web is provided extending along the first axis with further lateral webs protruding from the central web and extending along a second axis.

4. The blade according to claim 1, wherein the blade further comprises lateral wall elements, wherein the lateral wall elements are connected with each other and/or with webs by at least one bridge element.

5. The blade according to claim 1, wherein at least some of the webs extend along the second axis which is perpendicular to the first axis, wherein a clearance is provided at least in a side surface facing in the direction of the second axis.

6. The blade according to claim 1, wherein an edge formed between a side surface and the upper surface is a rounded edge.

7. The blade according to claim 1, wherein at least some of the webs are provided with a further concave clearance formed between a side surface and the upper surface forming an edge with the side surface.

8. The blade according to claim 7, wherein the concave clearance and the further concave clearance are spaced from each other by a portion of side surface.

9. An electric shaver comprising a motor, at least one slit cutter having an elongated outer blade according to claim 1, and an inner blade driven by said motor to move in sliding contact with the outer blade.

10. The shaver according to claim 9, wherein at least one guard is provided adjacent to the slit cutter, wherein the at least one guard has a comb structure with teeth and slots provided between the teeth.

11. The shaver according to claim 9, wherein the shaver further comprises at least one foil-type cutter which is driven by the motor.

12. A method for producing an elongated outer blade according to claim 1 comprising the steps of: providing a foil of a metallic material comprising a number of slits and webs, applying a protective layer at least on regions of at least one side of the webs, exposing the at least one side of the webs to an etching agent thereby forming a concave clearance between a side surface and the lower surface of the respective web.

13. The method according to claim 12, wherein the protective layer comprises a photoresist, wherein regions of the at least one side of the webs are exposed to light, thereby selectively curing the photoresist, and wherein un-cured photoresist is removed prior to exposing the at least one side of the webs to the etching agent.

14. The method according to claim 12, wherein the protective layer is removed after exposing the at least one side of the webs to the etching agent.

15. The method according to claim 12, wherein at least one rounded edge is formed between a side surface and the upper surface of at least some of the webs by an abrasive method.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 shows a three-dimensional view of an electric shaver.

[0020] FIG. 2 shows a top view of the shaver of FIG. 1.

[0021] FIG. 3 shows a perspective view of a prior art upper blade and a lower blade.

[0022] FIG. 4 shows a sectional view of an upper blade according to the invention with a lower blade.

[0023] FIG. 5 shows a sectional view of an alternative upper blade according to the invention with a lower blade.

[0024] FIG. 6 shows a perspective view of an alternative upper blade according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0025] The invention is disclosed in the following by way of exemplary embodiments realizing different features and aspects of the invention.

[0026] FIG. 1 is an example for an electric shaver 1 comprising a body 2 which may house a, preferably rechargeable, battery and/or an electric motor. A shaver head 3 is, e.g. in a releasable manner, attached to the body 2. As can be seen in FIG. 2, the shaver head 3 comprises two foil-type cutter units 4, 5 and a slit cutter 6 which is arranged interposed between the foil-type cutters 4, 5. The foil-type cutter units 4, 5 typically comprise a foil-type outer blade with a plurality of openings allowing hairs to pass there through and an inner blade driven by the motor to perform an oscillating movement during use to shear off hairs. Drive pins 2a may be provided for transmitting a driving motion or force from the motor to the foil-type cutter units 4, 5 and to slit cutter 6. The foil-type cutter units 4, 5 and slit cutter 6 are elongate components which substantially extend along a first longitudinal axis I. A second axis II extends in a direction perpendicular to the first axis I.

[0027] The design of a slit cutter 6 is shown in FIG. 3 in more detail. The slit cutter 6 comprises an outer blade 7 and an inner blade 8 driven by the motor to perform an oscillating movement during use to shear off hairs. The inner blade 8 may comprise a series of arch-shaped elements (cf. FIGS. 4 and 5). In the embodiment of FIG. 3, the outer blade 7 has an elongate form extending along the first axis I. The outer blade 7 comprises a central web 9 extending along the first axis I and a series of lateral webs 10 extending along the second axis II which is perpendicular to the first axis I. In other words, outer blade 7 of FIG. 3 has an H-shaped configuration. Slits 11 are provided between lateral webs 10. Lateral webs 10 and slits 11 provide for a comb-like configuration of the outer blade 7.

[0028] As an alternative to the H-shaped configuration, the outer blade may have a meander shape as shown in FIG. 2. The outer blade of FIG. 2 has a single web with the form of a wiggly line forming slits between the arches.

[0029] FIG. 4 shows an outer blade according to a first embodiment of the invention. In the depicted embodiment, the outer blade 7 has the H-shaped configuration of FIG. 3 with a central web 9 and lateral webs 10 with slits 11 between the lateral webs 10. However, the design of the outer blade 7 may depart from the H-shaped configuration and may have a meander shape, for example. In FIG. 4 the lateral webs 10 have an upper surface 12, a lower surface 13 and a side surface 14 facing in the direction of the second axis II. The upper edge 15 between the upper surface 12 and the side surface 14 is designed as a rounded edge to reduce skin irritations during contact with the skin. As an alternative, the upper edge 15 may have a substantially rectangular form. The rounded upper edge 15 may be formed by an abrasive method, e.g. buffing, preferably without exerting high mechanical and/or thermal loads to the outer blade 7.

[0030] A concave clearance 16 is provided adjacent to the lower surface 13 and the side surface 14. A sharp edge 17 is formed by the clearance 16 at the position where the clearance 16 meets with the side surface 14. The concave surface of clearance 16 forms an obtuse angle with the side surface 14 at edge 17. As an alternative, this angle may be rectangular or acute.

[0031] The clearance 16 has the effect of reducing the height of lateral web 10 at its lateral end. This facilitates that the lateral web 10 passes between the skin and a hair, thereby guiding the hair towards the central web 9 and the inner blade 8. The concave shape of clearance 16 further supports the guiding function of the lateral side of web 10. With this design, outer blade 7 improves the shaving result especially for hairs having an orientation substantially parallel to the skin without causing skin irritation.

[0032] A similar embodiment is depicted in FIG. 5. Again, the outer blade 7 has the H-shaped configuration of FIG. 3 with a central web 9 and lateral webs 10 with slits 11 between the lateral webs 10. Further, the embodiment of FIG. 5 features the concave clearance 16 forming sharp edge 17. However, instead of the rounded upper edge 15 a further concave clearance 18 is formed between a side surface 14 and the upper surface 12, thereby forming an additional edge 19 with the side surface 14. Clearance 16 and further clearance 18 are spaced from one another such that a small portion of side surface 14 remains between edges 17 and 19. In a not shown alternative embodiment the size and position of clearances 16, 18 may be chosen such that edges 17, 19 are identical, i.e. without a remaining portion of side surface 14.

[0033] The design of outer blade 7 with two clearances may further improve the shaving result for hairs having an orientation substantially parallel to the skin. However, due to the additional edge 19 facing towards the user's skin, this design may be subject to skin irritation. To reduce possible skin irritations, guards 20 are arranged parallel to the outer blade 7.

[0034] Guards 20 may have a comb-like configuration with teeth 21 and slots 22 formed between teeth 21. The comb-like design of guards 20 may guide hairs into an orientation facilitating shearing and/or introducing the hairs in slits 11 of outer blade 7. Teeth 21 may have a rounded outer contour as shown in FIG. 5 to avoid skin irritations. Such guards 20 are also shown in FIGS. 1 and 2. Alternative guards are depicted in FIG. 3.

[0035] FIG. 6 shows a still further embodiment of an outer blade 7 of a slit cutter 6. The outer blade 7 comprises to oppositely disposed side walls 23 and a series of lateral webs 24. The lateral webs 24 are connected to the side walls 23 by vertically extending portions 25. In addition, bridge elements 26 are provided which are substantially U-shaped and connect the side walls 23. Clearances 27 are provided on the lower edge of the lateral tips of lateral webs 24, thereby generating a sharp edge 28 in the respective side surface of webs 24.

[0036] Given that the outer blade 7 has to be relatively thin to slide between the skin and a hair, production of the clearances 16 and/or 18 is difficult without damaging the structure of outer blade 7. A suitable method for producing outer blade 7 comprises the steps of providing a foil of a metallic material comprising the slits 11 and webs 9, 10, applying a protective layer at least on regions of at least one side of the webs 9 and/or 10, and exposing the at least one side of the webs to an etching agent thereby forming the concave clearance(s) 16, 18.

[0037] The production of the outer blade 7 using etching to provide the clearances has the benefit that the foil is not subjected to mechanical and/or thermal loads. Thus, the design of the previously formed structure of slits 11 and webs 9, 10 is not affected. In addition, an etching process is suitable for mass production of outer blades with high precision and high reproducibility.

[0038] If the etching process is based on photo-etching, the protective layer typically comprises a photoresist, i.e. an agent which may be cured by, e.g. UV, light and which is suitable to protect the material of the foil from the etching agent. The clearances are formed by applying the protective layer to the foil and by exposing regions, for example the region of the lower surface 13 which is intended to remain between the clearances 16, of the at least one side of the webs 9, 10 to light. This light exposure selectively cures the photoresist. Thereafter, un-cured photoresist, which defines the regions to be etched, is removed prior to exposing the at least one side of the webs to the etching agent. The etching agent may flow against the respective surface of the foil, thereby hollowing out the concave clearance. The cured protective layer may be removed after exposing the at least one side of the webs 9, 10 to the etching agent.

[0039] While FIGS. 4 to 6 show clearances 16, 18 only on lateral sides of lateral webs 10, such clearances (and respective edges 17, 19) may be provided at any desired position of the outer blade 7. For example, clearances may extend parallel to the second axis II and/or may be provided on central web 9. Further, a meander shaped web or other web structures may be fully or partially provided with clearances and respective edges.

[0040] The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.”

[0041] Every document cited herein, including any cross referenced or related patent or application and any patent application or patent to which this application claims priority or benefit thereof, is hereby incorporated herein by reference in its entirety unless expressly excluded or otherwise limited. The citation of any document is not an admission that it is prior art with respect to any invention disclosed or claimed herein or that it alone, or in any combination with any other reference or references, teaches, suggests or discloses any such invention. Further, to the extent that any meaning or definition of a term in this document conflicts with any meaning or definition of the same term in a document incorporated by reference, the meaning or definition assigned to that term in this document shall govern.

[0042] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.