Abstract
A hair cutting appliance includes a stationary blade having a first wall portion arranged to serve as a skin facing wall when in operation; and a second wall portion offset from the first wall portion such that the first and second wall portions a guide slot that receives a movable cutter blade. A toothed leading edge is jointly formed by the first and second wall portions. Teeth at the toothed leading edge include a first leg defined by the first wall portion, and a second leg defined by the second wall portion. The first and second wall portions are connected at a frontal end of the toothed leading edge, thereby forming tips of the teeth. The second legs of the teeth are tapered along a portion of their longitudinal extension towards a bottom side of the stationary blade facing away from the skin, when in operation.
Claims
1. A blade for a blade set of a hair cutting appliance, said blade comprising: a first wall portion arranged at a top side of the blade, the top side being an outer side of the blade to serve as a skin facing wall during use; a second wall portion at a bottom side of the blade opposite the top side, the second wall portion being at least partially offset from the first wall portion such that the first wall portion and the second wall portion define therebetween a guide slot for receiving a movable cutter blade of the blade set; and at least one toothed leading edge jointly formed by the first wall portion and the second wall portion and including teeth, wherein at least one tooth of the teeth has a first leg defined by the first wall portion and a second leg defined by the second wall portion, and wherein the first leg has a cross section having a rectangular shape and the second leg of the at least one tooth has a cross section having a triangular shape.
2. The stationary blade as claimed in claim 1, wherein at least one of the first wall portion and the second wall portion comprises cutting edges for cooperating with corresponding cutting edges of the movable cutter blade, when in operation.
3. The blade as claimed in claim 1, comprising a first layer defining the first wall portion, a second layer defining the second wall portion and an intermediate layer arranged between the first layer and the second layer, wherein the first layer, the second layer and the intermediate layer are formed from metal material, wherein each of the first layer and the second layer is formed from a sheet metal blank, wherein the first layer and the second layer are bonded to one another via the intermediate layer thereby forming tips of the teeth, wherein the intermediate layer spaces the first layer and the second layer to define the guide slot therebetween, and wherein the intermediate layer forms a transitional intermediate wall portion at the tips of the teeth.
4. The blade as claimed in claim 1, wherein the blade is an integrally formed metal-plastic composite blade, wherein the first wall portion is at least partially made from metal sheet material, and wherein the second wall portion is at least partially made from plastic material that is molded to the metal sheet material.
5. The stationary blade as claimed in claim 1, further comprising a plastic component, wherein the triangular shape of the second leg of the at least one tooth is tapered along a direction away from the first leg in such a way that the second leg and the first leg are arranged in a non-symmetrical fashion with respect to one another, wherein the first wall portion and the second wall portion comprise an inner metal shell that is integrally made from a metal component, wherein the plastic component is molded to the metal component at a bottom side of the metal component facing away from the skin, and wherein the tapering of the second leg is at least partially formed by the plastic component.
6. A blade set for a hair cutting appliance, said blade set being arranged to be moved through hair in a moving direction to cut hair, said blade set comprising: the blade as claimed in claim 1, and a movable cutter blade comprising at least one toothed leading edge, said movable cutter blade being movably arranged within the guide slot defined by the blade, such that, upon relative motion between the movable cutter blade and the blade, the at least one toothed leading edge of the blade cooperates with corresponding teeth of the movable cutter blade to enable cutting of hair caught therebetween in a cutting action.
7. A hair cutting appliance comprising: a housing accommodating a motor; and the blade set as claimed in claim 6, wherein the blade is releasably attached to the housing, and wherein the movable cutter blade, in a mounted state, is operably connected to the motor, such that the motor is capable of linearly driving or rotating the movable cutter blade within in the guide slot of the blade.
8. The blade of claim 1, wherein the first and second legs are non-parallel and arranged in a non-symmetrical fashion, wherein the triangular shape of the second leg of the at least one tooth is such that the second leg is tapered extending from the bottom side to a tip of the of the second leg away from the first leg in such a way that the second leg and the first leg are arranged in the non-symmetrical fashion with respect to one another, and wherein the triangular shape of the second leg of the at least one tooth is such that the second leg is at least partially tapered towards a tip of the at least one tooth.
9. The blade of claim 1, wherein the triangular shape of the second leg is tapered such that the triangular shape extends from the bottom side to a tip of the second leg away from the first leg, and wherein the triangular shape of the second leg of the at least one tooth is such that the second leg is at least partially tapered towards a tip of the at least one tooth.
10. The stationary blade as claimed in claim 1, wherein lateral sides of the second leg of the at least one tooth are arranged at an inclination angle (γ) with respect to a vertical plane perpendicular to the first wall portion, wherein the inclination angle (γ) is from 3.0° to 30°.
11. The stationary blade as claimed in claim 1, wherein lateral sides of the second leg of the at least one tooth are arranged at an inclination angle (γ) with respect to a vertical plane perpendicular to the first wall portion, wherein the inclination angle (γ) is from 7.5° to 22.5°.
12. A stationary blade for a blade set of a hair cutting appliance, said stationary blade comprising: a first wall portion arranged at a top side of the blade, the top side being an outer side of the blade to serve as a skin facing wall during use; a second wall portion at a bottom side of the blade opposite the top side, the second wall portion being at least partially offset from the first wall portion such that the first wall portion and the second wall portion define therebetween a guide slot for receiving a movable cutter blade of the blade set; and at least one toothed leading edge jointly formed by the first wall portion and the second wall portion and including teeth, wherein at least one tooth of the teeth has a first leg defined by the first wall portion and a second leg defined by the second wall portion, wherein the first leg has a cross section having a rectangular shape, wherein lateral sides of the second leg of the at least one tooth are arranged at an inclination angle (γ) with respect to a vertical plane perpendicular to the first wall portion, and wherein the inclination angle (γ) is from 1.5° to 45°.
13. A blade for a blade set of a hair cutting appliance, said blade comprising: a first wall portion arranged at a top side of the blade, the top side being an outer side of the blade to serve as a skin facing wall during use; a second wall portion at a bottom side of the blade opposite the top side, the second wall portion being at least partially offset from the first wall portion such that the first wall portion and the second wall portion define therebetween a guide slot for receiving a movable cutter blade of the blade set; and at least one toothed leading edge jointly formed by the first wall portion and the second wall portion and including teeth, wherein at least one tooth of the teeth has a first leg defined by the first wall portion and a second leg defined by the second wall portion, wherein the first wall portion and the second wall portion are connected at a frontal end of the at least one toothed leading edge, thereby forming tips of the teeth including a tip of the at least one tooth, and wherein a cross section of the first leg at the first wall portion is rectangular, wherein the second leg is tapered in a direction away from the first leg, and wherein the first leg is larger in width than at least a bottom region of the second leg.
14. The stationary blade of claim 13, wherein a portion of the bottom region of the second leg has parallel walls.
15. A blade for a blade set of a hair cutting appliance, the blade comprising: a first wall portion arranged at a top side of the blade, the top side being an outer side of the blade to serve as a skin facing wall during use; a second wall portion at a bottom side of the blade opposite the top side, the second wall portion being at least partially offset from the first wall portion such that the first wall portion and the second wall portion define therebetween a guide slot for receiving a movable cutter blade of the blade set; and at least one toothed leading edge jointly formed by the first wall portion and the second wall portion and including teeth, wherein at least one tooth of the teeth has a first leg defined by the first wall portion and a second leg defined by the second wall portion, and wherein a cross section of the first leg has a rectangular shape, and a cross section of the second leg has one of a triangular shape, a trapezoid shape and a half-elliptical shape.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter. In the following drawings
(2) FIG. 1 shows a schematic perspective view of an exemplary hair cutting appliance including a cutting head implementing a blade set;
(3) FIG. 2 shows a perspective top view of a blade set of a cutting head for a hair cutting appliance;
(4) FIG. 3 shows a partial top view of an exemplary embodiment of a blade set;
(5) FIG. 4 shows a cross-sectional lateral side view of the blade set as shown in FIG. 3 taken along the line IV-IV in FIG. 3;
(6) FIG. 5 is a partial longitudinal side view of the blade set as shown in FIG. 3 and FIG. 4, wherein an orientation of the view of FIG. 5 is indicated by the line V-V in FIG. 4, and wherein the movable cutter blade has been omitted for illustrative purposes;
(7) FIG. 6 is another partial cross-sectional longitudinal side view of the arrangement of FIG. 5 taken along the line VI-VI in FIG. 4;
(8) FIG. 7 is a partial perspective longitudinal side view of an embodiment of a stationary blade for a blade set;
(9) FIG. 8 is a partial perspective longitudinal side view of yet another embodiment of a stationary blade for a blade set;
(10) FIG. 9 is a partial simplified schematic cross-sectional lateral side view of an embodiment of a stationary blade;
(11) FIG. 10 is a partial simplified schematic bottom view of an exemplary embodiment of a stationary blade;
(12) FIG. 11 is a partial cross-sectional longitudinal side view of the arrangement of FIG. 10 taken along the line XI-XI in FIG. 10;
(13) FIG. 12 is a partial simplified schematic bottom view of yet another exemplary embodiment of a stationary blade;
(14) FIG. 13 is a partial cross-sectional longitudinal side view of the arrangement of FIG. 12 taken along the line XIII-XIII in FIG. 12;
(15) FIG. 14 is a partial simplified schematic cross-sectional longitudinal side view of an embodiment of a tooth of a stationary blade;
(16) FIG. 15 is a partial simplified schematic cross-sectional longitudinal side view of another embodiment of a tooth of a stationary blade;
(17) FIG. 16 partial is a simplified schematic cross-sectional longitudinal side view of yet another embodiment of a tooth of a stationary blade;
(18) FIG. 17 is a partial simplified schematic cross-sectional longitudinal side view of: still another embodiment of a teeth of a stationary blade;
(19) FIG. 18 is a partial simplified schematic cross-sectional longitudinal side view of still yet another embodiment of a tooth of a stationary blade;
(20) FIG. 19 is a partial simplified schematic longitudinal side view of the arrangement of FIG. 18;
(21) FIG. 20 is a perspective top view of another embodiment of a blade set;
(22) FIG. 21 is a perspective bottom view of the blade set as shown in FIG. 20;
(23) FIG. 22 is an exploded perspective bottom view of the blade set shown in FIG. 20 and FIG. 21;
(24) FIG. 23 is a perspective exploded bottom view of another embodiment of a blade set;
(25) FIG. 24 is a perspective bottom view of a sheet metal component that may form part of yet another embodiment of a blade set;
(26) FIG. 25 is a partial perspective bottom view of the sheet metal component as shown in FIG. 24 in a bent state;
(27) FIG. 26 is a partial perspective cross-sectional view of a stationary blade comprising a sheet metal component as shown in FIG. 25;
(28) FIG. 27 is a perspective exploded bottom view of an embodiment of a blade set including a stationary blade as shown in FIG. 26;
(29) FIG. 28 is a perspective top view of a circular arrangement of a stationary blade for another embodiment of a blade set;
(30) FIG. 29 is a partial side view of the stationary blade as shown in FIG. 28; and
(31) FIG. 30 is a partial cross-sectional side view of the arrangement of FIG. 29.
DETAILED DESCRIPTION OF THE EMBODIMENTS
(32) FIG. 1 schematically illustrates, in a simplified perspective view, an exemplary embodiment of the hair cutting appliance 10, particularly an electric hair cutting appliance. The hair cutting appliance 10 may comprise a housing or, more particularly, a housing portion 12, a motor indicated by a dashed block 14 in the housing portion 12, and a drive mechanism or drive train indicated by a dashed block 16 in the housing portion 12. For powering the motor 14, at least in some embodiments of the hair cutting appliance 10, an electrical battery, indicated by a dashed block 18 in the housing portion 12, may be provided, such as, for instance, a rechargeable battery, a replaceable battery, etc. However, in some embodiments, the cutting appliance 10 may be further provided with a power cable for connecting a power supply. A power supply connector may be provided in addition or in the alternative to the (internal) electric battery 18.
(33) The hair cutting appliance 10 may further comprise a cutting head 20. At the cutting head 20, a blade set 22 may be attached to the hair cutting appliance 10. The blade set 22 may be driven by the motor 14 via the drive mechanism or drive train 16 to enable a cutting motion. The cutting motion may generally be regarded as a relative motion between a stationary blade and a movable cutter blade which will be further described and discussed hereinafter. Generally, a user may grasp, hold and manually guide cutting appliance 10 through hair in a moving direction 30 to cut hair. The cutting appliance 10 may be generally regarded as a hand-guided or hand-operated electrically powered device. Furthermore, the cutting head 20 or, more particularly, the blade set 22 can be connected to the housing portion 12 of the cutting appliance 10 in a pivotable manner, refer to the curved double-arrow indicated by reference numeral 28 in FIG. 1. In some applications, the cutting appliance 10 can be moved along skin to cut hair growing at the skin. When cutting hair closely to the skin, basically a shaving operation can be performed aiming at cutting or chopping hair at the level of the skin. However, also clipping (or trimming) operations may be envisaged, wherein the cutting head 20 comprising the blade set 22 is passed along a path at a desired distance relative to the skin.
(34) When being guided through hair, the cutting appliance 10 including the blade set 22 is typically moved along a common moving direction which is indicated by the reference numeral 30 in FIG. 1. It is worth mentioning in this connection that, given that the hair cutting appliance 10 is typically manually guided and moved, the moving direction 30 thus not necessarily has to be construed as a precise geometric reference having a fixed definition and relation with respect to the orientation of the hair cutting appliance 10 and its cutting head 20. That is, an overall orientation of the hair cutting appliance 10 with respect to the to-be-cut hair at the skin may be construed as somewhat unsteady. However, for illustrative purposes, it may be fairly assumed that the (imaginary) moving direction 30 is parallel (or generally parallel) to a main central plane of a coordinate system which may serve in a following as a means for describing structural feature of the hair cutting appliance 10.
(35) For ease of reference, coordinate systems are indicated in several drawings herein. By way of example, a Cartesian coordinate system X-Y-Z is indicated in FIG. 1. An axis X of the respective coordinate system extends in a generally longitudinal direction that is generally associated with length, for the purpose of this disclosure. An axis Y of the coordinate system extends in a lateral (or transverse) direction associated with width, for the purpose of this disclosure. An axis Z of the coordinate system extends in a height (or vertical) direction which may be referred to for illustrative purposes, at least in some embodiments, as a generally vertical direction. It goes without saying that an association of the coordinate system X-Y-Z to characteristic features and/or embodiment of the hair cutting appliance 10 is primarily provided for illustrative purposes and shall not be construed in a limiting way. It should be understood that those skilled in the art may readily convert and/or transfer the coordinate system provided herein when being confronted with alternative embodiments, respective figures and illustrations including alternative orientations. It is further worth mentioning that, for the purpose of the present disclosure, the coordinate system X-Y-Z is generally aligned with main directions and orientations of the cutting head 20, particularly of the blade set 22 thereof.
(36) FIG. 2 shows a perspective top view of a blade set 22 that may be implemented in the cutting head 20 illustrated in FIG. 1. The blade set 22 comprises a stationary blade 24 and a cutter blade 26 that may be moved with respect to the stationary blade 24 in a reciprocating motion. The stationary blade 24 and the cutter blade 26 may jointly define at least one toothed leading edge 32, 34, preferably a first toothed leading edge 32 and a second toothed leading edge 34. The first toothed leading edge 32 and the second toothed leading edge 34 are arranged in parallel fashion and facing away from each other. The movable cutter blade 26 is indicated in FIG. 2 in a dashed representation. The cutter blade 26 may be driven by a drive shaft 50 in a reciprocating manner. Consequently, the cutter blade 26 and the stationary blade 24 may be reciprocatingly moved with respect to each other and therefore cooperate to cut hairs that enter slots between teeth 38 of the stationary blade 24 and teeth 40 of the cutter blade 26 at the respective leading edges 32, 34 when the hair cutting appliance 10 is moved through hair in the moving direction 30.
(37) The stationary blade 24 may be arranged as a guard for the movable cutter blade 26. It is particularly preferred that the stationary blade 24 comprises a first wall portion and a secondary wall portion which are at least partially spaced from each other such that a guide slot for the cutter blade 26 is defined therebetween, refer also to the cross-sectional representations of the blade set 22 in FIGS. 4, 5 and 6. As a consequence, the stationary blade 24 may also cover the cutter blade 26 at the at least one toothed leading edge 32, 34.
(38) As already indicated above, the blade set 22 may be particularly suited for shaving and trimming operations. Shaving performance and trimming performance may be further improved when the blade set 22 is capable of following an actual skin contour. Consequently, it is particularly preferred that the blade set 22 is attachable to the housing portion 12 of the hair cutting appliance 10 in a pivotable fashion. A swiveling mechanism is indicated in FIG. 2 by reference numeral 42. The blade set 22 is attached to the swiveling mechanism 42. The swiveling mechanism 42 may form a part of the cutting head 20 that is interposed between the blade set 22 and the housing portion 12. The swiveling mechanism 42 may define a pivot or, rather, a virtual pivot for the blade set 22, refer to the curved double-arrow 28 in FIGS. 1 and 2.
(39) So as to define a maximum swiveling angle of the blade set 22 with respect to the housing portion 12, the swiveling mechanism 42 may comprise a limit stop 44 that may cooperate with a contact surface 46 to define an allowed range of the swiveling motion. By way of example, the swiveling mechanism 42 may be arranged as a four-bar-linkage mechanism. In this embodiment, the swiveling mechanism 42 comprises a base link 52 that may be attached to the housing portion 12. A first side link 54 and a second side link 56 may be coupled to the base link 52. At a top end thereof, the swiveling mechanism 42 may comprise a top link 58 that connects the first side link 54 and the second side link 56. Between the respective links 52, 54, 56, 58 hinges may be provided, particularly living hinges, that enable relative rotation between neighboring links and thus the overall pivoting motion.
(40) Generally, at least in some embodiments, the cutting head 20 may be regarded as a replaceable and/or a detachable cutting head. To this end, the cutting 20 may comprise an attachment interface 48 which is arranged to engage a respective receiving interface at the housing portion 12 of the hair cutting appliance 10. Particularly, the cutting head 20 may be arranged as a plug-in cutting head 20. As already indicated above, the blade set 22, particularly the cutter blade 26 thereof, may be coupled to the drive shaft 50. The drive shaft 50 may comprise an eccentric portion that may revolve about a longitudinal axis of the drive shaft 50. Consequently, an eccentric drive mechanism 16 may be provided for driving the cutter blade 26 in a reciprocating fashion with respect to the stationary blade 24.
(41) Being fitted with the swiveling mechanism 42 as exemplarily illustrated in FIG. 2 or with another exemplary embodiment of a swiveling mechanism, the cutting head 20 may be particularly suited for shaving operations. However, it is further preferred that the hair cutting appliance 10 is also suited for hair trimming operations. Hair trimming may involve cutting hairs at a desired length. The desired remaining length of the hairs may be defined by a so-called attachment comb.
(42) FIG. 3 is a partial top view of a blade set 22 that is basically arranged in accordance with the arrangement of the blade set 22 as shown in FIG. 2. FIG. 4 is a corresponding cross-sectional lateral side view. As indicated by an arrow that is designated by reference numeral 60 in FIG. 3, the movable cutter blade 26 may be operated so as to be moved with respect to the stationary blade 24 in a reciprocating fashion. As a consequence, respective teeth 38 of the stationary blade 24 and teeth 40 of the movable cutter blade 26 may cooperate to cut hairs therebetween. As can be further seen from FIG. 3, a lateral end portion 62 may be provided at respective lateral ends of the stationary blade 24. As indicated in FIG. 4, a top side or skin-facing side of the blade set 22 is indicated by reference numeral 36. Correspondingly, a side that is opposite to the top side 36 which may be therefore referred to as bottom side or as a side that is facing away from the skin is designated in FIG. 4 by reference numeral 64.
(43) At respective longitudinal ends of the teeth 38 of the stationary blade 24, tips 66 are provided. At respective longitudinal ends of the teeth 40 of the movable cutter blade 26, tips 68 are provided. As can be best seen from FIG. 4, the tips 66 of the teeth 38 protrude beyond the tips 68 of the teeth 40 in the longitudinal direction X. Furthermore, as a first wall portion 70 and a second wall portion 72 is provided at the stationary blade 24, the teeth 38 thereof including their tips 66 may somewhat embrace, cover or guard the teeth 40 of the movable cutter blade 26 including their tips 68. Furthermore, as a somewhat closed design of the stationary blade 26 is achieved in this way, the stationary blade 24 may be arranged in a considerably stiff and rigid fashion. The first wall portion 70 and the second wall portion 72 of the stationary blade 24 are spaced from each other so as to define a guide slot 74 therebetween. An effective height h.sub.s of the guide slot 74 is indicated in FIG. 6. Preferably, the height h.sub.s of the guide slot 74 is adapted to the height or thickness of the movable cutter blade 26 so as to enable a tight fit arrangement of the movable cutter blade in the guide slot 74.
(44) As can be further seen from FIG. 4 (refer also to FIG. 23), a transmitter 76 may be provided at and coupled to the cutter blade 26. The transmitter 76 is basically arranged to be engaged by the drive shaft 50 as shown in FIG. 2. Furthermore, a guide arrangement 78, particularly a longitudinal guide arrangement 78 that defines the longitudinal position of the movable cutter blade 26 with respect to the stationary blade may be provided at the bottom side (second wall portion 72) of the stationary blade 24. The guide arrangement 78 may for instance comprise an at least partially laterally extending slot in which the transmitter 76 is received in a sliding fashion.
(45) As already indicated above, the teeth 38 of the stationary blade 24 are basically defined by the first wall portion 70, at the top side 36, and the second wall portion 72, at the bottom side 64. In other words, the teeth 38, when viewed in a cross-sectional lateral side view, may comprise a basically U-shaped cross section. Hence, a first leg 80 and a second leg 82 may be provided and respectively defined by the first wall portion 70 and the second wall portion 72. The teeth 40 of the movable cutter blade 26 are received between the first leg 80 and the second leg 82.
(46) Between neighboring teeth 38 of the stationary blade 24 respective tooth slots 84 may be provided which may be also referred to as slot spaces. Basically, to-be-cut hairs have to enter the tooth slots 84 to be cut or chopped therein in a cooperating cutting action between the stationary blade 24 and the movable cutter blade 26. FIG. 5 and FIG. 6 show partial longitudinal side views of the stationary blade 24 as illustrated in FIGS. 3 and 4. For illustrative purposes, the movable cutter blade 26 is not shown in FIGS. 5 and 6. Respective lines V-V and VI-VI in FIG. 4 indicate the orientation and position of the views of FIG. 5 and FIG. 6. The arrangement as illustrated in FIG. 5 and FIG. 6 is conventional insofar as the longitudinal cross section or profile of the teeth 38 or, more particularly, their first legs 80 and second legs 82 is basically rectangular. As a consequence, also the tooth slots 84 are arranged in a basically rectangular fashion. An overall height II, of the tooth slots 84 is indicated in FIG. 6. The overall height II, is basically composed of the height h.sub.s of the guide slot 74, the height h.sub.t of the first leg 80 and the height h.sub.b of the second leg 82. A width w.sub.s of the tooth slots 84 is indicated in FIG. 6 as well.
(47) As further indicated in FIG. 6, the stationary blade 24 may be arranged at least in some embodiments as described herein as an integrally formed metal plastic composite part. By way of example, a metal component 86 may be provided that forms at least a substantial part of the first wall portion 70 or the first leg 80. Furthermore, a plastic component 88 may be provided that may form at least a substantial part of the second wall portion 72 or the second leg 82. Forming the stationary blade 24 as a composite component that comprises a metal component 86 and a plastic component 88 may have the advantage that particularly the second legs 82 of the teeth 38 may be adequately shaped in a vertically tapered fashion so as to improve the hair catching capability of the blade set 22. As can be further seen from FIG. 6, a cutting plane 90 may be defined by the bottom side of the first wall portion 70 or, more particularly, of the first legs 80 of the teeth 38 that is opposite to the top side or top face 36.
(48) Further reference is made to FIG. 5. As shown in FIG. 5 and in the corresponding top view of FIG. 3, the tips 66 of the teeth 38 may be provided with a respective longitudinally extending tip tapering 92. The longitudinal tapering 92 may be arranged such that, when viewed in a top view orientation as shown in FIG. 3, the tooth slots 84 are arranged in a basically funnel-like, constricted or tapered fashion.
(49) Further reference is made to FIGS. 7 and 8 illustrating slightly tilted (about the lateral axis Y) longitudinal side views of two exemplary embodiments of stationary blades 24. In other words, the vertical direction or height direction Z indicated by an arrow of the coordinate system of FIGS. 7 and 8 is somewhat inclined with respect to the view orientation plane thereof. FIG. 7 shows a conventional arrangement of a respective double-walled stationary blade 24 that comprises a first wall portion 70 and a second wall portion 72 that define therebetween a guide slot 74. Furthermore, a series of teeth 38 is provided that alternate with respective tooth slots 84. The teeth 38 and the tooth slots 84 are provided with basically rectangular shapes and outlines when viewed in a longitudinal side view, refer also to the cross-sectional illustration of FIG. 6 that describes a similar arrangement.
(50) At the tips 66 of the teeth 38, a longitudinal tip tapering 92 may be provided. However, at a rear portion of the teeth 38, the respective second legs 82 may comprise a basically rectangular cross section. This may have the effect that only hair filaments 94 that are arranged at a considerably large angle α (alpha) may enter the tooth slots 84 with little efforts. In case the angle of orientation a between the hair filaments 94 and the skin surface becomes too small, the hair catching performance of the stationary blade 24 may be deteriorated.
(51) Therefore, in accordance with an aspect of the present disclosure, it may be advantageous to arrange lateral side surfaces 96 of the second legs 82 of the teeth 38 in a tilted or inclined manner with respect to a basically vertical plane that is defined by the longitudinal direction X and the vertical direction Z. Further reference is made to FIG. 8. As a consequence, a (vertical) tapering 98 may be provided at the teeth 38, particularly at the second legs 82 thereof. This may have the advantage that hair filaments 94 that are arranged in a basically flat fashion with respect to the skin surface may still easily enter the tooth slots 84, refer to FIG. 8. By providing the vertical tapering 98 at the teeth 38, also hair filaments 94 that are arranged at a considerably small angle β (beta) with respect to the skin may be efficiently caught and cut. As a consequence, particularly the shaving or trimming performance of the blade set 22 may be increased. The more hairs may enter the tooth slots 84 at a single stroke, the quicker the hair cutting operation may be eventually accomplished. Also at the rear ends of the tooth slots 84, as shown in FIG. 8, a conical section 100 which may also be referred to as tapered section or funnel section may be provided.
(52) Reference is made to FIGS. 9 to 13 illustrating exemplary embodiments of teeth 38 of stationary blades 24 that are arranged in a beneficial tapered fashion.
(53) As can be best seen from FIG. 9, the stationary blade 24 may be composed of a metal component 86 and a plastic component 88. As with the embodiment of FIG. 9, the metal component 86 forms a substantial part of the first wall portion 70 and therefore also of the first legs 80. Further, the plastic component 88 forms the second wall portion 72 and, as a consequence, the second leg 82. At the tips 66 of the teeth 38, the first wall portion 70 and the second wall portion 72 are coupled to each other via an intermediate wall portion 104. As with the embodiment of FIG. 9, the intermediate wall portion 104 is primarily formed by the plastic component 88.
(54) It can be further seen from FIG. 9 that the guide slot 74 does not necessarily have to comprise a rectangular profile. Primarily at the first wall portion 70, an even cutting plane 90 may be provided at the first legs 80 of the teeth 38. However, at the bottom side of the guide slot 74 not in each case a respective plane surface needs to be provided, refer to the corresponding top surface 114 of the second legs 82.
(55) FIG. 10 and FIG. 11 illustrate a bottom view and a corresponding longitudinal cross-sectional side view of a first embodiment of a tapering of the teeth 38. FIG. 12 and FIG. 13 illustrate a bottom view and a corresponding longitudinal cross-sectional side view of a second embodiment of a respective tapering of the teeth 38. The location of the cross section of FIGS. 11 and 13 is indicated in FIGS. 9, 10, and 12 by respective lines XI-XI and XIII-XIII.
(56) The embodiment of FIGS. 10 and 11 comprises a longitudinally extending tapering 92 that is basically provided at the tips 66 of the teeth 38. Adjacent to the longitudinal tapering 92, a vertically extending tapering 98 is provided. In other words, at least at the side surfaces 96, the outer profile of the respective second legs 82 may be basically constant along a substantial portion of their longitudinal extension shown in FIG. 11 as having parallel walls from which the tapering 98 extends vertically towards the tip 66.
(57) However, as can be clearly seen from FIG. 9, at a top side or top surface 114 of the second legs 82, the respective cross section of the second legs 82 may vary along their longitudinal extension. In other words, the top surface 114 may be curved with respect to the longitudinal direction X.
(58) A cross section of the second wall portion 72 or, rather, the second leg 82 is indicated by reference numeral 110 in FIGS. 11 and 13. A corresponding cross section of the first wall portion 70 and the first leg 80 is indicated by reference numeral 108 in FIGS. 11 and 13.
(59) In contrast to the arrangement as shown in FIGS. 10 and 11, the arrangement of FIGS. 12 and 13 comprises a cross section 110 that gradually changes along the longitudinal extension of the second leg 82. In other words, adjacent to the tip 66, the cross section 110 is significantly smaller in size than adjacent to a rear end of the second leg 82 that is opposite to the tip 66. Basically the same may apply to the cross section 108 of the first leg 80.
(60) In both FIGS. 11 and 13, the cross section 110 is arranged in a basically trapezoid fashion. In other words, the side surfaces 96 are provided with a respective tapering 98 and therefore inclined with respect to each other. The side surfaces 96 extend between the top surface 114 and a bottom surface 116 that is facing away from the skin. Generally, the bottom surface 116 is smaller than the top surface 114. The same applies to the embodiment of FIG. 13.
(61) Reference is made to FIGS. 14 to 19, illustrating further embodiments of respective taperings 92, 98 of teeth 38 that may improve the hair catching capabilities of the stationary blade 24. In each of the embodiments of FIGS. 14 to 19, the first leg 80 that is defined by the first wall portion 70 is basically arranged in a rectangularly profiled fashion. By contrast, the second leg 82 that is formed by the second wall portion 72 is arranged in a basically tapered fashion. The tapering may comprise a longitudinal tapering 92 which may also be referred to as tip tapering. Further, a vertical tapering 98 may be provided that is present at the respective cross sections or profiles as shown in FIGS. 14 to 18.
(62) FIG. 14 illustrates an embodiment that may basically correspond to the embodiment as shown in FIGS. 10 and 11. Correspondingly, a cross section 110 of the second leg 82 may be provided that is shaped in a basically trapezoid fashion. The cross section 110 may be constant along a considerable portion of the longitudinal extension of the second leg 92 of the teeth 38. The side surfaces 96 may be arranged at an angle γ (gamma) with respect to a vertical plane is defined by the vertical direction Z and the longitudinal direction X. The angle of inclination γ may be in the range of about 0.5° to about 45°, preferably in the range of about 3° to about 30°, more preferably in the range of about 3° to about 22.5°. Furthermore, needless to say, the edges of the cross section or profile of the second leg 82 may be rounded or chamfered. Due to the tapering of the profile or cross section 110, the width w.sub.2 of the bottom surface 116 may be significantly smaller than the corresponding width w.sub.1 of the top surface 114.
(63) The cutting plane 90 provided at the top side of the guide slot 74 is defined by cutting edges 120 provided at the first wall portion 70 or first leg 80. In some embodiments, also the second wall portion 72 or the second leg 82 may be provided with respective cutting edges 122 adjacent to the guide slot 74. The cutting edges 120 and, if any, the cutting edges 122 may corporate with corresponding cutting edges of the movable cutter blade 26 to cut hair.
(64) FIGS. 15 to 19 illustrate embodiments wherein the vertical tapering 98 is overlayed or superimposed by a further tapering 92 that is basically extending in the longitudinal direction, as with the embodiment of FIGS. 12 and 13. As a result, the cross section 110 is gradually reduced towards the tips 66 of the respective teeth 38. By contrast, as with the embodiments of FIGS. 10, 11, and 14, the cross section 110 is basically constant along a substantial portion of its longitudinal extension.
(65) FIGS. 15 and 16 illustrate embodiments that implement a trapezoid cross section or profile 110. FIG. 17 illustrates an embodiment that implements a triangular cross section 110. FIG. 18 illustrates an embodiment that implements a half-elliptical cross section 110. FIG. 19 is a corresponding lateral side view (not including a cross-sectional representation) of the view of FIG. 18.
(66) As with the embodiments of FIGS. 15 and 17, the height h.sub.b or thickness of the cross section 110 of the second leg 82 is basically constant along at least part of its longitudinal extension. As with the embodiment of FIGS. 16 and 18, the respective height h.sub.b is gradually reduced towards the tips 66 of the teeth.
(67) It goes without saying that the desired tapering (vertical tapering 98 which may be overlayed by a longitudinal tapering 92) of the second legs 82 of the teeth 38 may be provided by further alternative shapes and outlines. Generally, the tapering is intended to increase the hair catching capability of the stationary blade 24. The tapering may be arranged such that, when viewed in a longitudinal side view, profiles or outlines of the tooth slots 84 that are provided between respective) teeth 38 may be arranged in a basically Y-like fashion or funnel-like fashion including a widening at the bottom side and a narrowing at the tip side. This provides the stationary blade 24 with the capability of catching and cutting also hairs that are arranged at a considerably flat fashion with respect to the skin surface.
(68) Further reference is made to FIGS. 20 to 30 illustrating several alternative embodiments of stationary blades 24. In each case, the stationary blade 24 is arranged as a double-sided or double-walled stationary blade 24 such that a respective guide slot 74 is provided wherein a movable cutter blade may be received.
(69) A first exemplary arrangement of a blade set 130 is illustrated in FIGS. 20, 21, and 22. FIG. 20 shows a perspective top view of the blade set 130. FIG. 21 shows a perspective bottom view of the blade set 130. FIG. 22 shows a perspective exploded bottom view of the blade set 130. It is worth mentioning in this connection that the exploded state of the stationary blade 24 as shown in FIG. 22 does not necessarily have to correspond to an actual present state of the respective components thereof in practice in the course of manufacturing the stationary blade 24.
(70) As with the embodiment of FIGS. 20, 21, and 22, the stationary blade 24 is arranged as a layered stack that is basically composed of a first wall portion 70, a second wall portion 72 and an intermediate wall portion 104 that is interposed therebetween. Each of the wall portions 70, 72, 104 may be obtained from a respective sheet metal blank. Particularly the intermediate wall portion 104 may be processed so as to define the guide slot 74 between the first wall portion 70 and the second wall portion 72. In other words, the height of a sheet metal blank the intermediate wall portion 104 is obtained from basically corresponds to the height h.sub.s of the guide slot 74. In the guide slot 74 the movable cutter blade 26 may be slidingly received. Furthermore, at the level of the intermediate wall portion 104, a central guide plate 132 may be defined which cooperates with a corresponding laterally extending guide slot of the movable cutter blade 26 so as to receive the movable cutter blade 26 in a defined manner.
(71) In the course of manufacturing the stationary blade 24, initially the sheet metal blanks the respective wall portions 70, 72, 104 may be formed from may be present as basically continuously extending components or layers 136, 138, 140. In other words, the first wall portion 70 may be defined by a first layer 136. The second wall portion 72 may be defined by a second layer 138. The intermediate wall portion 104 may be defined by a third (intermediate) layer 140.
(72) Hence, no perforation, slots or similar elements may be provided at the initial state. Furthermore, the respective sheet metal blanks may be present in an oversized fashion (in terms of their longitudinal and/or lateral extension). This may have the advantage that, particularly with the intermediate wall portion 104, respective material removing operations may be performed so as to define for instance the guide slot 74, the wall portions 70, 72, 104 may be handled and processed with little efforts.
(73) After an initial (rough) processing of at least some of the respective wall portions 70, 72, 104, the wall portions 70, 72, 104 may be bonded to each other. To this end, for instance laser bonding, laser welding and similar processes may be utilized. In the bonded state, further material removing processing may be performed. For instance, the teeth 38 may be processed to obtain their desired shape. In this way, a first toothed leading edge 32 and a second toothed leading edge 34 may be obtained. Furthermore, a desired outline of the stationary blade 24 may be processed so as to receive the final or close-to-final product. Therefore, again referring to the exploded view of FIG. 22, the intermediate wall portion 104 in isolation is typically not present in the fragmented state as shown in FIG. 22. As the intermediate wall portion 104 is bonded to the first wall portion 70 and the second wall portion 72, a single integrally shaped layered stack may be processed. Therefore, tooth portions 134 that remain after the respective material removing processing are shown in FIG. 22 primarily for illustrative purposes as separate entities. The embodiment of the stationary blade 24 as shown in FIG. 21 may have the advantage that the height or thickness of the wall portions 70, 72, 104 may be defined and selected independently. In other words, the respective wall portion 70, 72, 104 do not necessarily have to comprise the same thickness or height.
(74) So as to achieve the desired tapering at the second legs 82 of the second wall portion 72, the respective cross section or profile 110 may be processed accordingly without the need or requirement to process the first legs 80 of the first wall portion 70 accordingly.
(75) With particular reference to FIG. 23, a further embodiment of a blade set 150 is described that utilizes a stationary blade 24 that is arranged as an integrally formed metal plastic component. At least to some extent, the blade set 150 of FIG. 23 corresponds to the general design and layout of the blade set 22 illustrated in FIGS. 2 to 6. The blade set 150 is shown in FIG. 23 in a perspective exploded bottom view. Again, the state as shown in FIG. 23 thus not necessarily reflects an actual state of the respective components in the course of the manufacturing process as the stationary blade 24 is integrally formed. Hence, in practice for instance the plastic component 88 is not necessarily present in a separated state in isolation.
(76) The metal component 86 may be also referred to as insert component 152. The plastic component 88 may be also referred to as overmolded component 154. The metal component 86 basically defines the first wall portion 70, at least a substantial portion thereof including tooth stem portions 158 that are provided with the cutting edges 120 (refer to FIG. 14). The metal component 86 may be obtained from a sheet metal blank. The sheet metal blank may be processed accordingly so as to define the tooth stem portions 158. Then, the metal component 86 may be inserted in a mold in which plastic material may be injected so as to define the plastic component 88 which may also be referred to as overmolded component 154. The plastic component 88 may define the second wall portion 72 and an intermediate wall portion 104 where the first wall portion 70 and the second wall portion 72 are interconnected at their tips. Further, the plastic component 88 may define at least a fraction of the first wall portion 70, for instance adjacent to the tips 66 of the teeth 38, refer also to FIG. 4 and to FIG. 9 in this connection. Respective overmolded tooth portions that are defined by the plastic component 88 are indicated by reference numeral 160 in FIG. 23. Furthermore, the guide arrangement 78 as already described in connection with FIG. 4 may be formed in this way.
(77) FIG. 23 further shows an exemplary arrangement of the transmitter 76. For instance, the transmitter 76 may comprise a driving bridge 162 which may be coupled to the movable cutter blade 26, e.g. by bonding, welding or soldering. Furthermore, an engagement element 164 may be provided that may be coupled to the driving bridge 162. The engagement element 164 may be engaged by a drive shaft 50, refer also to FIG. 2 in this connection.
(78) Further reference is made to FIGS. 24 to 27 elucidating another exemplary embodiment of a blade set 170 that utilizes a stationary blade 24 that is arranged as an integrally shaped composite metal plastic component.
(79) As can be seen in FIG. 24, initially a sheet metal blank may be provided from which a metal sheet 172 may be obtained. The metal sheet 172 may be processed accordingly. For instance, respective rows of slots 174 may be processed. The metal sheet 172 may comprise a central portion 176 which defines a substantial portion of the first wall portion 70. Further, adjacent to the central portion 176, the metal sheet 172 may comprise end portions which may also be referred to as bent portions 178. The bent portions 178 are deformed, preferably bent over, so as to define an inner shell 192 of the stationary blade 24, refer also to FIG. 25. By way of example, a slot dummy 180 may be provided that occupies the space of the guide slot 74. Accordingly, a reference or gauge geometry may be provided. By bending the end portions 178 (e.g. by 180°), a closed loop or shell may be defined. Bonding spots 186 are indicated in FIG. 25. The respective end portions 178 may be bonded, particularly welded, to each other, for instance by line welding, spot welding, etc. Furthermore, actuation recesses 188 may be provided at the metal shell 192. As can be best seen from FIG. 27, the transmitter 76 may extend through the actuation recesses 188 so as to contact the movable cutter blade 26 to transmit or transfer the driving motion. The bent end portions 178 define at least a substantial portion of the second wall portion 72, refer also to FIG. 26. In the deformed state of the metal shell 192, semi-finished teeth 184 may be provided at respective toothed leading edges that comprise a basically U-shaped lateral cross section.
(80) The metal shell 192 as indicated in FIG. 25 may be then arranged in an injection-molding mold or cavity. In this context, the slot dummy 180 or a similar dummy component may be kept in the slot 74. Then, melted plastic material may be injected so as to define the plastic component 88 which may be also referred to as overmolded component 194. Accordingly, the plastic component 88 may form a substantial portion of the second wall portion 72 and at least a fraction of the first wall portion 70. Furthermore, the metal shell 192 defines an inner core of the stationary blade 24 and therefore may form a substantial portion of the first wall portion 70 and at least a significant portion of the second wall portion 72 that delimit the guide slot 74. The metal shell 192 and the overmolded component 194 may jointly define the intermediate wall portion 104 that connects the first wall portion 70 and the second wall portion 72.
(81) Further reference is made to FIGS. 28 to 30 illustrating a circular embodiment of a stationary blade 24 for a blade set 22. As already indicated, the coordinate system X-Y-Z is primarily presented for illustrative purposes. As can be best seen in FIG. 28, the circular embodiment of the stationary blade can be best described using a polar coordinate system that is having a central axis L that basically corresponds to the vertical axis or height-indicating axis Z of the (Cartesian) coordinate system X-Y-Z. The central axis L may also be regarded as a central axis of rotation. Furthermore, a radial direction or distance r originating from the central axis L is indicated in FIGS. 28, 29, and 30. In addition, a coordinate δ (delta) indicating an angular position may be provided depicting an angle between a reference radial direction and a present radial direction.
(82) Furthermore, a tangential direction is indicated by tin FIG. 28 which is basically perpendicular to the (imaginary) moving direction 30 and to the radial direction r of a currently observed tooth. In addition, a circumferential direction t′ is illustrated in FIGS. 28, 29, and 30 that indicates a circumferential and/or tangential direction. In other words, the tangential direction t is a tangent line to the circumferential direction t′ at a distinct point thereof that is described by an axial angle δ.
(83) It will be readily understood by those skilled in the art that several aspects of the present disclosure described in connection with at least one of the embodiments as described above are not limited to the particular disclosed (linear) embodiment and may be therefore readily transferred and applied to other embodiments, regardless of whether they are introduced and presented in connection with a Cartesian coordinate system or a cylindrical coordinate system. A cutting operation of a blade set 22 that implements a circular stationary blade 24 and a corresponding circular movable cutter blade 26 may be effected by a relative rotational movement between the movable cutter blade 26 (not shown in FIGS. 28 to 30) and the stationary blade 24. In other words, the respective cutting motion may be a one-directional rotational movement or an oscillating movement.
(84) Also the stationary blade 24 defines a top surface 36 that faces the skin when in operation. Apart from that, respective teeth 38 may be provided that may be arranged at a single circular toothed leading edge. As also the circular stationary blade 24 may be arranged as a double-sided or double-walled stationary blade, a first wall portion 70 and a second wall portion 72 may be present. Between the first wall portion 70 and the second wall portion 72, an intermediate wall portion 104 may be present. Therefore, consequently, also the teeth 38 of the circular stationary blade 38 may be arranged and shaped in accordance with at least one of the (linear) embodiments as described hereinbefore. With respect to the detailed structure of the circular stationary blade 24, several options may be envisaged including a layered stack arrangement as described in FIGS. 20 to 22, an integrally molded metal plastic composite arrangement including a metal component that basically defines a major portion of the first wall portion 70 as illustrated in FIG. 23, and an integrally formed metal plastic composite arrangement including an inner metal shell that defines and surrounds the guide slot and to which a plastic component is molded as illustrated in FIGS. 24 to 27.
(85) It is therefore worth mentioning in this connection that those skilled in the art understood that particularly a circular blade set 22 that implements a circular stationary blade 24 as shown in FIGS. 28 to 30 having a considerably large radius may be construed, for the sake of understanding, as an approximate linearly shaped blade set, particularly when only a portion or circular segment of the circular stationary blade 24 is observed. Consequently, also the Cartesian coordinate system X, Y, Z that is used herein for defining and explaining linear embodiments may be transferred and applied to the embodiment of FIGS. 28 to 30.
(86) While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.
(87) In the claims, the word “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single element or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.
(88) Any reference signs in the claims should not be construed as limiting the scope.
